diff --git a/app/app.pro b/app/app.pro
index 773237a..ac8f281 100644
--- a/app/app.pro
+++ b/app/app.pro
@@ -6,6 +6,7 @@ TARGET = $$MEDIAWRITER_NAME
 
 QT += qml quick widgets network
 
+LIBS += -lisomd5
 linux {
     LIBS += -lyaml-cpp
 }
diff --git a/app/dialogs/DownloadDialog.qml b/app/dialogs/DownloadDialog.qml
index 43c3f9b..0605ac0 100644
--- a/app/dialogs/DownloadDialog.qml
+++ b/app/dialogs/DownloadDialog.qml
@@ -195,6 +195,32 @@ Dialog {
                     }
                 }
             },
+            State {
+                name: "write_verifying_failed_no_drives"
+                when: releases.selected.variant.status === Variant.WRITE_VERIFYING_FAILED && drives.length <= 0
+                PropertyChanges {
+                    target: rightButton;
+                    text: qsTr("Retry");
+                    enabled: false;
+                    color: "red";
+                    onClicked: drives.selected.write(releases.selected.variant);
+                }
+            },
+            State {
+                name: "write_verifying_failed"
+                when: releases.selected.variant.status === Variant.WRITE_VERIFYING_FAILED && drives.length > 0
+                PropertyChanges {
+                    target: messageLoseData;
+                    visible: true;
+                }
+                PropertyChanges {
+                    target: rightButton;
+                    text: qsTr("Retry");
+                    enabled: true;
+                    color: "red";
+                    onClicked: drives.selected.write(releases.selected.variant);
+                }
+            },
             State {
                 name: "failed_download"
                 when: releases.selected.variant.status === Variant.DOWNLOAD_FAILED
@@ -446,6 +472,22 @@ Dialog {
                             text: qsTr("Writing this image type is not supported.")
                             color: "red"
                         }
+                        Text {
+                            visible: releases.selected.variant.noMd5sum
+                            font.pointSize: 10
+                            Layout.fillWidth: true
+                            width: Layout.width
+                            wrapMode: Text.WordWrap
+                            text: qsTr("This image won't be verified after writing because no MD5 sum was found.")
+                        }
+                        Text {
+                            visible: releases.selected.variant.isCompressed
+                            font.pointSize: 10
+                            Layout.fillWidth: true
+                            width: Layout.width
+                            wrapMode: Text.WordWrap
+                            text: qsTr("This image won't be verified after writing because it is a compressed image.")
+                        }
                         RowLayout {
                             height: rightButton.height
                             Layout.minimumWidth: parent.width
diff --git a/app/image_download.cpp b/app/image_download.cpp
index 74a51cb..19d5882 100644
--- a/app/image_download.cpp
+++ b/app/image_download.cpp
@@ -30,11 +30,12 @@
 #include <QStorageInfo>
 #include <QTimer>
 
-ImageDownload::ImageDownload(const QUrl &url_arg, const QString &filePath_arg)
+ImageDownload::ImageDownload(const QUrl &url_arg, const QString &filePath_arg, const QString &md5sum_arg)
 : QObject()
 , hash(QCryptographicHash::Md5) {
     url = url_arg;
     filePath = filePath_arg;
+    md5sum = md5sum_arg;
     file = nullptr;
     startingImageDownload = false;
     wasCancelled = false;
@@ -122,66 +123,13 @@ void ImageDownload::onImageDownloadFinished() {
     } else if (reply->error() == QNetworkReply::NoError) {
         qDebug() << this->metaObject()->className() << "Finished successfully";
 
-        qDebug() << this->metaObject()->className() << "Downloading md5";
+        if (md5sum.isEmpty()) {
+            // If md5sum doesn't exist, be lenient and
+            // don't treat this as a failed check.
+            // Instead, skip the check.
+            qDebug() << this->metaObject()->className() << "No md5sum found, so skipping md5 check";
 
-        const QString md5sumUrl = url.adjusted(QUrl::RemoveFilename).toString() + "/MD5SUM";
-        QNetworkReply *md5Reply = makeNetworkRequest(md5sumUrl);
-
-        connect(
-            md5Reply, &QNetworkReply::finished,
-            this, &ImageDownload::onMd5DownloadFinished);
-        connect(
-            this, &ImageDownload::cancelled,
-            md5Reply, &QNetworkReply::abort);
-    } else {
-        qDebug() << "Download was interrupted by an error:" << reply->errorString();
-        qDebug() << "Attempting to resume";
-
-        emit interrupted();
-
-        QTimer::singleShot(1000, this,
-            [this]() {
-                startImageDownload();
-            });
-    }
-}
-
-void ImageDownload::onMd5DownloadFinished() {
-    QNetworkReply *reply = qobject_cast<QNetworkReply *>(sender());
-    reply->deleteLater();
-
-    if (wasCancelled) {
-        return;
-    } else {
-        if (reply->error() == QNetworkReply::NoError) {
-            qDebug() << this->metaObject()->className() << "Downloaded MD5SUM successfully";
-
-            md5 = [this, reply]() {
-                const QByteArray md5sumBytes = reply->readAll();
-                const QString md5sumContents(md5sumBytes);
-
-                // MD5SUM is of the form "sum image \n sum image \n ..."
-                // Search for the sum by finding image matching url
-                const QStringList elements = md5sumContents.split(QRegExp("\\s+"));
-                QString prev = "";
-                for (int i = 0; i < elements.size(); ++i) {
-                    if (elements[i].size() > 0 && url.toString().contains(elements[i]) && prev.size() > 0) {
-                        return prev;
-                    }
-
-                    prev = elements[i];
-                }
-
-                return QString();
-            }();
-        } else {
-            qDebug() << this->metaObject()->className() << "Failed to download MD5SUM";
-
-            md5 = QString();
-        }
-
-        if (md5.isEmpty()) {
-            checkMd5(QString());
+            rename_to_final_name();
         } else {
             file->close();
             const bool open_success = file->open(QIODevice::ReadOnly);
@@ -194,6 +142,16 @@ void ImageDownload::onMd5DownloadFinished() {
                 finish(ImageDownload::Md5CheckFail);
             }
         }
+    } else {
+        qDebug() << "Download was interrupted by an error:" << reply->errorString();
+        qDebug() << "Attempting to resume";
+
+        emit interrupted();
+
+        QTimer::singleShot(1000, this,
+            [this]() {
+                startImageDownload();
+            });
     }
 }
 
@@ -212,7 +170,20 @@ void ImageDownload::computeMd5() {
         if (file->atEnd()) {
             const QByteArray sum_bytes = hash.result().toHex();
             const QString computedMd5 = QString(sum_bytes);
-            checkMd5(computedMd5);
+
+            const bool checkPassed = (computedMd5 == md5sum);
+
+            if (checkPassed) {
+                qDebug() << "MD5 check passed";
+
+                rename_to_final_name();
+            } else {
+                qDebug() << "MD5 mismatch";
+                qDebug() << "sum should be =" << md5sum;
+                qDebug() << "computed sum  =" << computedMd5;
+
+                finish(ImageDownload::Md5CheckFail);
+            }
         } else {
             QTimer::singleShot(0, this, &ImageDownload::computeMd5);
         }
@@ -246,39 +217,15 @@ void ImageDownload::startImageDownload() {
         reply, &QNetworkReply::abort);
 }
 
-void ImageDownload::checkMd5(const QString &computedMd5) {
-    const bool checkPassed = [this, computedMd5]() {
-        if (md5.isEmpty()) {
-            // Can fail to download md5 sum if:
-            // 1) Failed to download MD5SUM file
-            // 2) MD5SUM file is not present
-            // 3) MD5SUM file does not contain needed sum
-            // In all cases, DON'T treat this as a fail.
-            // Instead, skip the check.
-            qDebug() << this->metaObject()->className() << "Failed to download md5 sum, so skipping md5 check";
+void ImageDownload::rename_to_final_name() {
+    qDebug() << this->metaObject()->className() << "Renaming to final filename";
 
-            return true;
-        } else {
-            return (computedMd5 == md5);
-        }
-    }();
+    const bool rename_success = file->rename(filePath);
 
-    if (checkPassed) {
-        qDebug() << this->metaObject()->className() << "Renaming to final filename";
-
-        const bool rename_success = file->rename(filePath);
-
-        if (rename_success) {
-            finish(ImageDownload::Success);
-        } else {
-            finish(ImageDownload::DiskError, tr("Unable to rename the temporary file."));
-        }
+    if (rename_success) {
+        finish(ImageDownload::Success);
     } else {
-        qDebug() << "MD5 mismatch";
-        qDebug() << "sum should be =" << md5;
-        qDebug() << "computed sum  =" << computedMd5;
-
-        finish(ImageDownload::Md5CheckFail);
+        finish(ImageDownload::DiskError, tr("Unable to rename the temporary file."));
     }
 }
 
diff --git a/app/image_download.h b/app/image_download.h
index 9d1df31..684722f 100644
--- a/app/image_download.h
+++ b/app/image_download.h
@@ -54,7 +54,7 @@ public:
         Cancelled
     };
 
-    ImageDownload(const QUrl &url_arg, const QString &filePath_arg);
+    ImageDownload(const QUrl &url_arg, const QString &filePath_arg, const QString &md5sum_arg);
     Result result() const;
     QString errorString() const;
 
@@ -86,7 +86,6 @@ public slots:
 private slots:
     void onImageDownloadReadyRead();
     void onImageDownloadFinished();
-    void onMd5DownloadFinished();
     void computeMd5();
 
 private:
@@ -95,16 +94,15 @@ private:
 
     QUrl url;
     QString filePath;
+    QString md5sum;
     QFile *file;
     bool startingImageDownload;
     bool wasCancelled;
     QCryptographicHash hash;
 
-    QString md5;
-
     QString getFilePath() const;
     void startImageDownload();
-    void checkMd5(const QString &computedMd5);
+    void rename_to_final_name();
     void finish(const Result result_arg, const QString &errorString_arg = QString());
 };
 
diff --git a/app/linuxdrivemanager.cpp b/app/linuxdrivemanager.cpp
index 9ffaf99..195f675 100644
--- a/app/linuxdrivemanager.cpp
+++ b/app/linuxdrivemanager.cpp
@@ -220,6 +220,7 @@ bool LinuxDrive::write(Variant *variant) {
     args << "write";
     args << variant->filePath();
     args << m_device;
+    args << variant->md5sum();
 
     qDebug() << this->metaObject()->className() << "Helper command will be" << args;
     m_process->setArguments(args);
@@ -286,7 +287,9 @@ void LinuxDrive::onReadyRead() {
 
     m_progress->setCurrent(NAN);
 
-    m_variant->setStatus(Variant::WRITING);
+    if (m_variant->status() != Variant::WRITE_VERIFYING && m_variant->status() != Variant::WRITING) {
+        m_variant->setStatus(Variant::WRITING);
+    }
 
     while (m_process->bytesAvailable() > 0) {
         QString line = m_process->readLine().trimmed();
@@ -297,6 +300,14 @@ void LinuxDrive::onReadyRead() {
             m_progress->setMax(file.size());
 
             m_progress->setCurrent(0);
+
+            m_variant->setStatus(Variant::WRITING);
+        } else if (line == "CHECK") {
+            qDebug() << this->metaObject()->className() << "Helper finished writing, now it will check the written data";
+            const QFile file(m_variant->filePath());
+            m_progress->setMax(file.size());
+            m_progress->setCurrent(0);
+            m_variant->setStatus(Variant::WRITE_VERIFYING);
         } else if (line == "DONE") {
             m_variant->setStatus(Variant::WRITING_FINISHED);
             Notifications::notify(tr("Finished!"), tr("Writing %1 was successful").arg(m_variant->fileName()));
@@ -321,8 +332,12 @@ void LinuxDrive::onFinished(const int exitCode, const QProcess::ExitStatus statu
         QString errorMessage = m_process->readAllStandardError();
         qDebug() << "Writing failed:" << errorMessage;
         Notifications::notify(tr("Error"), tr("Writing %1 failed").arg(m_variant->fileName()));
-        if (m_variant->status() == Variant::WRITING) {
-            m_variant->setErrorString(errorMessage);
+
+        m_variant->setErrorString(errorMessage);
+
+        if (m_variant->status() == Variant::WRITE_VERIFYING) {
+            m_variant->setStatus(Variant::WRITE_VERIFYING_FAILED);
+        } else {
             m_variant->setStatus(Variant::WRITING_FAILED);
         }
     } else {
diff --git a/app/releasemanager.cpp b/app/releasemanager.cpp
index bd98a15..68446de 100644
--- a/app/releasemanager.cpp
+++ b/app/releasemanager.cpp
@@ -47,6 +47,7 @@ ReleaseManager::ReleaseManager(QObject *parent)
     metadata_urls_reply_group = nullptr;
     metadata_urls_backup_reply_group = nullptr;
     metadata_reply_group = nullptr;
+    md5sum_reply_group = nullptr;
 
     qDebug() << this->metaObject()->className() << "construction";
 
@@ -319,7 +320,7 @@ void ReleaseManager::onMetadataDownloaded() {
 
     loadReleases(sectionsFiles);
 
-    const QList<QString> imagesFiles = [&]() {
+    imagesFiles = [&]() {
         QList<QString> out;
 
         for (const QString &image_url : image_urls) {
@@ -329,15 +330,148 @@ void ReleaseManager::onMetadataDownloaded() {
         return out;
     }();
 
-    qDebug() << "Loading variants";
-
-    for (const QString &imagesFile : imagesFiles) {
-        loadVariants(imagesFile);
-    }
+    // NOTE: images/variants are loaded later after
+    // md5sum is downloaded
 
     delete metadata_reply_group;
     metadata_reply_group = nullptr;
 
+    const QList<QString> md5sum_url_list = [&]() {
+        const QList<QString> image_url_list = [&]() {
+            QList<QString> out;
+
+            for (const QString &imagesFile : imagesFiles) {
+                YAML::Node variants = YAML::Load(imagesFile.toStdString());
+
+                if (!variants["entries"]) {
+                    continue;
+                }
+
+                for (const YAML::Node &variantData : variants["entries"]) {
+                    const QString url = yml_get(variantData, "link");
+                    out.append(url);
+                }
+            }
+
+            return out;
+        }();
+
+        const QList<QString> out = [&]() {
+            // NOTE: using set because there will be
+            // duplicates due to there being multiple
+            // images per folder
+            QSet<QString> out_set;
+
+            for (const QString &image_url : image_url_list) {
+                // TODO: duplicating code in
+                // image_download.cpp
+                const QString md5sum_url = QUrl(image_url).adjusted(QUrl::RemoveFilename).toString() + "/MD5SUM";
+
+                out_set.insert(md5sum_url);
+            }
+
+            const QList<QString> out = out_set.toList();
+
+            return out;
+        }();
+
+        return out;
+    }();
+
+    downloadMD5SUM(md5sum_url_list);
+}
+
+void ReleaseManager::downloadMD5SUM(const QList<QString> &md5sum_url_list) {
+    qDebug() << "Downloading MD5SUM's";
+
+    md5sum_reply_group = new NetworkReplyGroup(md5sum_url_list, this);
+
+    connect(
+        md5sum_reply_group, &NetworkReplyGroup::finished,
+        this, &ReleaseManager::onMD5SUMDownloaded);
+}
+
+void ReleaseManager::onMD5SUMDownloaded() {
+    const QHash<QString, QNetworkReply *> replies = md5sum_reply_group->get_reply_list();
+
+    // Check that all replies suceeded
+    // If not, retry
+    // TODO: duplicating code
+    for (const QNetworkReply *reply : replies.values()) {
+        // NOTE: ignore ContentNotFoundError for
+        // metadata since it can happen if one of
+        // the files was moved or renamed. In that
+        // case it's fine to process other
+        // downloads and ignore this failed one.
+        const QNetworkReply::NetworkError error = reply->error();
+        const bool download_failed = (error != QNetworkReply::NoError && error != QNetworkReply::ContentNotFoundError);
+
+        if (download_failed) {
+            qDebug() << "Failed to download md5sum:" << reply->errorString() << reply->error() << "Retrying in 10 seconds.";
+            QTimer::singleShot(10000, this, &ReleaseManager::downloadMetadata);
+
+            delete md5sum_reply_group;
+            md5sum_reply_group = nullptr;
+
+            return;
+        }
+    }
+
+    qDebug() << "Downloaded md5sum, loading it";
+
+    const QList<QString> md5sum_file_list = [&]() {
+        QList<QString> out;
+
+        for (const QString &url : replies.keys()) {
+            QNetworkReply *reply = replies[url];
+
+            if (reply->error() == QNetworkReply::NoError) {
+                const QByteArray bytes = reply->readAll();
+                const QString string = QString(bytes);
+                out.append(string);
+            } else {
+                qDebug() << "Failed to download metadata from" << url;
+                qDebug() << "Error:" << reply->error();
+            }
+        }
+
+        return out;
+    }();
+
+    const QHash<QString, QString> md5sum_map = [&]() {
+        QHash<QString, QString> out;
+
+        for (const QString &file : md5sum_file_list) {
+            const QList<QString> line_list = file.split("\n");
+
+            // MD5SUM is of the form "sum image \n sum
+            // image \n ..."
+            for (const QString &line : line_list) {
+                const QList<QString> elements = line.split(QRegExp("\\s+"));
+
+                if (elements.size() != 2) {
+                    continue;
+                }
+
+                const QString md5sum = elements[0];
+                const QString filename = elements[1];
+
+                out[filename] = md5sum;
+            }
+        }
+
+        return out;
+    }();
+
+    qDebug() << "Loading variants";
+
+    for (const QString &imagesFile : imagesFiles) {
+        loadVariants(imagesFile, md5sum_map);
+    }
+
+    delete md5sum_reply_group;
+    md5sum_reply_group = nullptr;
+
     setDownloadingMetadata(false);
 }
 
@@ -376,7 +510,7 @@ ReleaseFilterModel *ReleaseManager::getFilterModel() const {
     return filterModel;
 }
 
-void ReleaseManager::loadVariants(const QString &variantsFile) {
+void ReleaseManager::loadVariants(const QString &variantsFile, const QHash<QString, QString> &md5sum_map) {
     YAML::Node variants = YAML::Load(variantsFile.toStdString());
 
     if (!variants["entries"]) {
@@ -434,6 +568,13 @@ void ReleaseManager::loadVariants(const QString &variantsFile) {
             }
         }();
 
+        const QString md5sum = [&]() {
+            const QString filename = QUrl(url).fileName();
+            const QString out = md5sum_map[filename];
+
+            return out;
+        }();
+
         // qDebug() << QUrl(url).fileName() << releaseName << architecture_name(arch) << board << file_type_name(fileType) << (live ? "LIVE" : "");
 
         // Find a release that has the same name as this variant
@@ -449,7 +590,7 @@ void ReleaseManager::loadVariants(const QString &variantsFile) {
         }();
 
         if (release != nullptr) {
-            Variant *variant = new Variant(url, arch, fileType, board, live, this);
+            Variant *variant = new Variant(url, arch, fileType, board, live, md5sum, this);
             release->addVariant(variant);
         } else {
             qDebug() << "Failed to find a release for this variant!" << url;
diff --git a/app/releasemanager.h b/app/releasemanager.h
index 2370977..6386381 100644
--- a/app/releasemanager.h
+++ b/app/releasemanager.h
@@ -29,6 +29,7 @@
  */
 
 #include <QObject>
+#include <QHash>
 
 class Release;
 class ReleaseModel;
@@ -73,19 +74,23 @@ private:
     NetworkReplyGroup *metadata_reply_group;
     NetworkReplyGroup *metadata_urls_reply_group;
     NetworkReplyGroup *metadata_urls_backup_reply_group;
+    NetworkReplyGroup *md5sum_reply_group;
     QList<QString> section_urls;
     QList<QString> image_urls;
+    QList<QString> imagesFiles;
 
-    void loadVariants(const QString &variantsFile);
+    void loadVariants(const QString &variantsFile, const QHash<QString, QString> &md5sum_map);
     void setDownloadingMetadata(const bool value);
     void downloadMetadataUrls();
     void onMetadataUrlsDownloaded();
     void downloadMetadataUrlsBackup();
     void onMetadataUrlsBackupDownloaded();
     void downloadMetadata();
+    void downloadMD5SUM(const QList<QString> &md5sum_url_list);
     void loadReleases(const QList<QString> &sectionsFiles);
     void addReleaseToModel(const int index, Release *release);
     void onMetadataDownloaded();
+    void onMD5SUMDownloaded();
 };
 
 #endif // RELEASEMANAGER_H
diff --git a/app/variant.cpp b/app/variant.cpp
index 9268797..82d72cf 100644
--- a/app/variant.cpp
+++ b/app/variant.cpp
@@ -33,13 +33,14 @@
 #include <QFileInfo>
 #include <QStandardPaths>
 
-Variant::Variant(const QString &url, const Architecture arch, const FileType fileType, const QString &board, const bool live, QObject *parent)
+Variant::Variant(const QString &url, const Architecture arch, const FileType fileType, const QString &board, const bool live, const QString &md5sum, QObject *parent)
 : QObject(parent) {
     m_url = url;
     m_fileName = QUrl(url).fileName();
     m_filePath = QDir(QStandardPaths::writableLocation(QStandardPaths::DownloadLocation)).filePath(fileName());
     m_board = board;
     m_live = live;
+    m_md5sum = md5sum;
     m_arch = arch;
     m_fileType = fileType;
     m_status = Variant::PREPARING;
@@ -53,6 +54,7 @@ Variant::Variant(const QString &path, QObject *parent)
     m_filePath = path;
     m_board = QString();
     m_live = false;
+    m_md5sum = QString();
     m_arch = Architecture_UNKNOWN;
     m_fileType = file_type_from_filename(path);
     m_status = Variant::READY_FOR_WRITING;
@@ -71,6 +73,10 @@ QString Variant::fileTypeName() const {
     return file_type_name(m_fileType);
 }
 
+QString Variant::md5sum() const {
+    return m_md5sum;
+}
+
 QString Variant::name() const {
     QString out = architecture_name(m_arch) + " | " + m_board;
 
@@ -93,6 +99,14 @@ bool Variant::canWrite() const {
     return file_type_can_write(m_fileType);
 }
 
+bool Variant::noMd5sum() const {
+    return md5sum().isEmpty();
+}
+
+bool Variant::isCompressed() const {
+    return (m_fileType == FileType_TAR_XZ || m_fileType == FileType_IMG_XZ);
+}
+
 Progress *Variant::progress() {
     return m_progress;
 }
@@ -168,7 +182,7 @@ void Variant::download() {
         setStatus(READY_FOR_WRITING);
     } else {
         // Download image
-        auto download = new ImageDownload(QUrl(url()), filePath());
+        auto download = new ImageDownload(QUrl(url()), filePath(), md5sum());
 
         connect(
             download, &ImageDownload::started,
diff --git a/app/variant.h b/app/variant.h
index 74fb7e0..56db20f 100644
--- a/app/variant.h
+++ b/app/variant.h
@@ -59,6 +59,8 @@ class Variant final : public QObject {
     Q_PROPERTY(QString fileName READ fileName CONSTANT)
     Q_PROPERTY(QString fileTypeName READ fileTypeName CONSTANT)
     Q_PROPERTY(bool canWrite READ canWrite CONSTANT)
+    Q_PROPERTY(bool noMd5sum READ noMd5sum CONSTANT)
+    Q_PROPERTY(bool isCompressed READ isCompressed CONSTANT)
     Q_PROPERTY(Progress *progress READ progress CONSTANT)
 
     Q_PROPERTY(Status status READ status NOTIFY statusChanged)
@@ -76,6 +78,8 @@ public:
         READY_FOR_WRITING,
         WRITING,
         WRITING_FINISHED,
+        WRITE_VERIFYING,
+        WRITE_VERIFYING_FAILED,
         WRITING_FAILED
     };
     Q_ENUMS(Status)
@@ -89,10 +93,12 @@ public:
         {READY_FOR_WRITING, tr("Ready to write")},
         {WRITING, tr("Writing")},
         {WRITING_FINISHED, tr("Finished!")},
+        {WRITE_VERIFYING, tr("Checking the written data")},
+        {WRITE_VERIFYING_FAILED, tr("The written data is corrupted")},
         {WRITING_FAILED, tr("Error")},
     };
 
-    Variant(const QString &url, const Architecture arch, const FileType fileType, const QString &board, const bool live, QObject *parent);
+    Variant(const QString &url, const Architecture arch, const FileType fileType, const QString &board, const bool live, const QString &md5sum, QObject *parent);
 
     // Constructor for local file
     Variant(const QString &path, QObject *parent);
@@ -106,7 +112,10 @@ public:
     QString filePath() const;
     QString fileName() const;
     QString fileTypeName() const;
+    QString md5sum() const;
     bool canWrite() const;
+    bool noMd5sum() const;
+    bool isCompressed() const;
     Progress *progress();
 
     Status status() const;
@@ -135,6 +144,7 @@ private:
     QString m_filePath;
     QString m_board;
     bool m_live;
+    QString m_md5sum;
     Architecture m_arch;
     FileType m_fileType;
     Status m_status;
diff --git a/app/windrivemanager.cpp b/app/windrivemanager.cpp
index e503c8c..5f4eb0d 100644
--- a/app/windrivemanager.cpp
+++ b/app/windrivemanager.cpp
@@ -291,6 +291,7 @@ bool WinDrive::write(Variant *variant) {
     args << "write";
     args << variant->filePath();
     args << QString("%1").arg(m_device);
+    args << variant->md5sum();
     m_child->setArguments(args);
 
     qDebug() << this->metaObject()->className() << "Starting" << m_child->program() << args;
@@ -360,7 +361,12 @@ void WinDrive::onFinished(const int exitCode, const QProcess::ExitStatus exitSta
         Notifications::notify(tr("Finished!"), tr("Writing %1 was successful").arg(m_variant->fileName()));
     } else {
         m_variant->setErrorString(m_child->readAllStandardError().trimmed());
-        m_variant->setStatus(Variant::WRITING_FAILED);
+
+        if (m_variant->status() == Variant::WRITE_VERIFYING) {
+            m_variant->setStatus(Variant::WRITE_VERIFYING_FAILED);
+        } else {
+            m_variant->setStatus(Variant::WRITING_FAILED);
+        }
     }
 
     m_child->deleteLater();
@@ -393,7 +399,9 @@ void WinDrive::onReadyRead() {
 
     m_progress->setCurrent(NAN);
 
-    m_variant->setStatus(Variant::WRITING);
+    if (m_variant->status() != Variant::WRITE_VERIFYING && m_variant->status() != Variant::WRITING) {
+        m_variant->setStatus(Variant::WRITING);
+    }
 
     while (m_child->bytesAvailable() > 0) {
         QString line = m_child->readLine().trimmed();
@@ -406,6 +414,12 @@ void WinDrive::onReadyRead() {
         } else if (line == "DONE") {
             m_variant->setStatus(Variant::WRITING_FINISHED);
             Notifications::notify(tr("Finished!"), tr("Writing %1 was successful").arg(m_variant->fileName()));
+        } else if (line == "CHECK") {
+            qDebug() << this->metaObject()->className() << "Written media check starting";
+            const QFile file(m_variant->filePath());
+            m_progress->setMax(file.size());
+            m_progress->setCurrent(0);
+            m_variant->setStatus(Variant::WRITE_VERIFYING);
         } else {
             bool ok;
             qreal bytes = line.toLongLong(&ok);
diff --git a/helper/linux/linux.pro b/helper/linux/linux.pro
index c406185..f81fcfa 100644
--- a/helper/linux/linux.pro
+++ b/helper/linux/linux.pro
@@ -5,6 +5,8 @@ QT += core network dbus
 CONFIG += link_pkgconfig
 PKGCONFIG += liblzma
 
+LIBS += -lisomd5
+
 CONFIG += c++11
 CONFIG += console
 
diff --git a/helper/linux/main.cpp b/helper/linux/main.cpp
index 8cd223e..33a4f3c 100644
--- a/helper/linux/main.cpp
+++ b/helper/linux/main.cpp
@@ -36,8 +36,8 @@ int main(int argc, char *argv[]) {
 
     if (app.arguments().count() == 3 && app.arguments()[1] == "restore") {
         new RestoreJob(app.arguments()[2]);
-    } else if (app.arguments().count() == 4 && app.arguments()[1] == "write") {
-        new WriteJob(app.arguments()[2], app.arguments()[3]);
+    } else if (app.arguments().count() == 5 && app.arguments()[1] == "write") {
+        new WriteJob(app.arguments()[2], app.arguments()[3], app.arguments()[4]);
     } else {
         QTextStream err(stderr);
         err << "Helper: Wrong arguments entered";
diff --git a/helper/linux/writejob.cpp b/helper/linux/writejob.cpp
index 0ac38ae..339b309 100644
--- a/helper/linux/writejob.cpp
+++ b/helper/linux/writejob.cpp
@@ -40,6 +40,8 @@
 
 #include <lzma.h>
 
+#include "isomd5/libcheckisomd5.h"
+
 typedef QHash<QString, QVariant> Properties;
 typedef QHash<QString, Properties> InterfacesAndProperties;
 typedef QHash<QDBusObjectPath, InterfacesAndProperties> DBusIntrospection;
@@ -59,10 +61,11 @@ public:
     size_t size;
 };
 
-WriteJob::WriteJob(const QString &what, const QString &where)
+WriteJob::WriteJob(const QString &what, const QString &where, const QString &md5_arg)
 : QObject(nullptr)
 , what(what)
-, where(where) {
+, where(where)
+, md5(md5_arg) {
     qDBusRegisterMetaType<Properties>();
     qDBusRegisterMetaType<InterfacesAndProperties>();
     qDBusRegisterMetaType<DBusIntrospection>();
@@ -75,6 +78,19 @@ WriteJob::WriteJob(const QString &what, const QString &where)
     QTimer::singleShot(0, this, SLOT(work()));
 }
 
+int WriteJob::staticOnMediaCheckAdvanced(void *data, long long offset, long long total) {
+    return ((WriteJob*)data)->onMediaCheckAdvanced(offset, total);
+}
+
+int WriteJob::onMediaCheckAdvanced(long long offset, long long total) {
+    QTextStream out(stdout);
+
+    Q_UNUSED(total);
+    out << offset << "\n";
+    out.flush();
+    return 0;
+}
+
 QDBusUnixFileDescriptor WriteJob::getDescriptor() {
     QTextStream err(stderr);
 
@@ -264,6 +280,55 @@ bool WriteJob::writePlain(int fd) {
     return true;
 }
 
+bool WriteJob::check(int fd) {
+    QTextStream out(stdout);
+    QTextStream err(stderr);
+
+    if (what.endsWith(".xz")) {
+        out << "NOT CHECKING BECAUSE IMAGE IS ZIPPED\n";
+        out << "DONE\n";
+        out.flush();
+        err << "OK\n";
+        err.flush();
+        qApp->exit(0);
+        return false;
+    }
+
+    if (md5.isEmpty()) {
+        out << "NOT CHECKING BECAUSE NO MD5 IS PROVIDED\n";
+        out << "DONE\n";
+        out.flush();
+        err << "OK\n";
+        err.flush();
+        qApp->exit(0);
+        return false;
+    }
+
+    out << "CHECK\n";
+    out.flush();
+    switch (mediaCheckFD(fd, md5.toLocal8Bit().data(), &WriteJob::staticOnMediaCheckAdvanced, this)) {
+    case ISOMD5SUM_CHECK_NOT_FOUND:
+    case ISOMD5SUM_CHECK_PASSED:
+        out << "DONE\n";
+        out.flush();
+        err << "OK\n";
+        err.flush();
+        qApp->exit(0);
+        return false;
+    case ISOMD5SUM_CHECK_FAILED:
+        err << tr("Your drive is probably damaged.") << "\n";
+        err.flush();
+        qApp->exit(1);
+        return false;
+    default:
+        err << tr("Unexpected error occurred during media check.") << "\n";
+        err.flush();
+        qApp->exit(1);
+        return false;
+    }
+    return true;
+}
+
 void WriteJob::work() {
     QTextStream out(stdout);
     QTextStream err(stderr);
@@ -293,15 +358,16 @@ void WriteJob::work() {
     const bool write_success = write(fd.fileDescriptor());
 
     if (write_success) {
-        out.flush();
-        err << "DONE\n";
-        qApp->exit(0);
+        check(fd.fileDescriptor());
     } else {
         qApp->exit(4);
     }
 }
 
 void WriteJob::onFileChanged(const QString &path) {
+    QTextStream out(stdout);
+    QTextStream err(stderr);
+
     const bool still_downloading = QFile::exists(path);
     if (still_downloading) {
         return;
@@ -313,7 +379,16 @@ void WriteJob::onFileChanged(const QString &path) {
         return;
     }
 
-    work();
+    out << "WRITE\n";
+    out.flush();
+
+    const bool write_success = write(fd.fileDescriptor());
+
+    if (write_success) {
+        check(fd.fileDescriptor());
+    } else {
+        qApp->exit(4);
+    }
 }
 
 PageAlignedBuffer::PageAlignedBuffer(const size_t page_count) {
diff --git a/helper/linux/writejob.h b/helper/linux/writejob.h
index 7ed876e..ed1c0ad 100644
--- a/helper/linux/writejob.h
+++ b/helper/linux/writejob.h
@@ -43,12 +43,16 @@
 class WriteJob : public QObject {
     Q_OBJECT
 public:
-    explicit WriteJob(const QString &what, const QString &where);
+    explicit WriteJob(const QString &what, const QString &where, const QString &md5_arg);
+
+    static int staticOnMediaCheckAdvanced(void *data, long long offset, long long total);
+    int onMediaCheckAdvanced(long long offset, long long total);
 
     QDBusUnixFileDescriptor getDescriptor();
     bool write(int fd);
     bool writeCompressed(int fd);
     bool writePlain(int fd);
+    bool check(int fd);
 public slots:
     void work();
 private slots:
@@ -57,6 +61,7 @@ private slots:
 private:
     QString what;
     QString where;
+    QString md5;
     QDBusUnixFileDescriptor fd;
     QFileSystemWatcher watcher;
 };
diff --git a/helper/win/main.cpp b/helper/win/main.cpp
index 9fc8c87..f857ef0 100644
--- a/helper/win/main.cpp
+++ b/helper/win/main.cpp
@@ -36,8 +36,8 @@ int main(int argc, char *argv[]) {
 
     if (app.arguments().count() == 3 && app.arguments()[1] == "restore") {
         new RestoreJob(app.arguments()[2]);
-    } else if (app.arguments().count() == 4 && app.arguments()[1] == "write") {
-        new WriteJob(app.arguments()[2], app.arguments()[3]);
+    } else if (app.arguments().count() == 5 && app.arguments()[1] == "write") {
+        new WriteJob(app.arguments()[2], app.arguments()[3], app.arguments()[4]);
     } else {
         QTextStream err(stderr);
         err << "Helper: Wrong arguments entered\n";
diff --git a/helper/win/win.pro b/helper/win/win.pro
index afeceaf..206d991 100644
--- a/helper/win/win.pro
+++ b/helper/win/win.pro
@@ -4,7 +4,7 @@ include($$top_srcdir/deployment.pri)
 
 QT += core network
 
-LIBS += -llzma
+LIBS += -lisomd5 -llzma
 
 CONFIG += c++11
 CONFIG += console
diff --git a/helper/win/writejob.cpp b/helper/win/writejob.cpp
index ff4382e..4c7e5ab 100644
--- a/helper/win/writejob.cpp
+++ b/helper/win/writejob.cpp
@@ -35,11 +35,15 @@
 
 #include <lzma.h>
 
+#include "isomd5/libcheckisomd5.h"
+
 const int BLOCK_SIZE = 512 * 128;
 
-WriteJob::WriteJob(const QString &what, const QString &where)
+WriteJob::WriteJob(const QString &what, const QString &where, const QString &md5_arg)
 : QObject(nullptr)
-, what(what) {
+, what(what)
+, md5(md5_arg)
+{
     bool ok = false;
     this->where = where.toInt(&ok);
 
@@ -50,6 +54,19 @@ WriteJob::WriteJob(const QString &what, const QString &where)
     QTimer::singleShot(0, this, &WriteJob::work);
 }
 
+int WriteJob::staticOnMediaCheckAdvanced(void *data, long long offset, long long total) {
+    return ((WriteJob*)data)->onMediaCheckAdvanced(offset, total);
+}
+
+int WriteJob::onMediaCheckAdvanced(long long offset, long long total) {
+    QTextStream out(stdout);
+
+    Q_UNUSED(total);
+    out << offset << "\n";
+    out.flush();
+    return 0;
+}
+
 HANDLE WriteJob::openDrive(int physicalDriveNumber) {
     QTextStream err(stderr);
 
@@ -240,9 +257,7 @@ void WriteJob::work() {
     }
 
     if (write_success) {
-        out.flush();
-        err << "DONE\n";
-        qApp->exit(0);
+        check();
     } else {
         qApp->exit(4);
     }
@@ -415,6 +430,9 @@ bool WriteJob::writePlain(HANDLE drive) {
 }
 
 void WriteJob::onFileChanged(const QString &path) {
+    QTextStream out(stdout);
+    QTextStream err(stderr);
+
     const bool still_downloading = QFile::exists(path);
     if (still_downloading) {
         return;
@@ -426,5 +444,78 @@ void WriteJob::onFileChanged(const QString &path) {
         return;
     }
 
-    work();
+    // NOTE: let the app know that writing started
+    out << "WRITE\n";
+    out.flush();
+
+    bool write_success = write();
+
+    // NOTE: try to write 2 times and sleep between
+    // attempts. Apparently needed on windows.
+    if (!write_success) {
+        out << "0\n";
+        out.flush();
+        QThread::sleep(5);
+
+        write_success = write();
+    }
+
+    if (write_success) {
+        check();
+    } else {
+        qApp->exit(4);
+    }
+}
+
+bool WriteJob::check() {
+    QTextStream out(stdout);
+    QTextStream err(stdout);
+
+    if (what.endsWith(".xz")) {
+        out << "NOT CHECKING BECAUSE IMAGE IS ZIPPED\n";
+        out << "DONE\n";
+        out.flush();
+        err << "OK\n";
+        err.flush();
+        qApp->exit(0);
+        return true;
+    }
+
+    if (what.endsWith(".xz")) {
+        out << "NOT CHECKING BECAUSE NO MD5 IS PROVIDED\n";
+        out << "DONE\n";
+        out.flush();
+        err << "OK\n";
+        err.flush();
+        qApp->exit(0);
+        return true;
+    }
+
+    out << "CHECK\n";
+    out.flush();
+
+    HANDLE drive = openDrive(where);
+
+    switch (mediaCheckFD(_open_osfhandle(reinterpret_cast<intptr_t>(drive), 0), md5.toLocal8Bit().data(), &WriteJob::staticOnMediaCheckAdvanced, this)) {
+    case ISOMD5SUM_CHECK_NOT_FOUND:
+    case ISOMD5SUM_CHECK_PASSED:
+        out << "DONE\n";
+        out.flush();
+        err << "OK\n";
+        err.flush();
+        qApp->exit(0);
+        break;
+    case ISOMD5SUM_CHECK_FAILED:
+        err << tr("Your drive is probably damaged.") << "\n";
+        err.flush();
+        qApp->exit(1);
+        return false;
+    default:
+        err << tr("Unexpected error occurred during media check.") << "\n";
+        err.flush();
+        qApp->exit(1);
+        return false;
+    }
+
+    return true;
 }
diff --git a/helper/win/writejob.h b/helper/win/writejob.h
index 6dc020a..52ebd0a 100644
--- a/helper/win/writejob.h
+++ b/helper/win/writejob.h
@@ -36,7 +36,10 @@
 class WriteJob : public QObject {
     Q_OBJECT
 public:
-    explicit WriteJob(const QString &what, const QString &where);
+    explicit WriteJob(const QString &what, const QString &where, const QString &md5_arg);
+
+    static int staticOnMediaCheckAdvanced(void *data, long long offset, long long total);
+    int onMediaCheckAdvanced(long long offset, long long total);
 
 private:
     HANDLE openDrive(int physicalDriveNumber);
@@ -60,8 +63,11 @@ private slots:
 private:
     QString what;
     uint where;
+    QString md5;
 
     QFileSystemWatcher watcher;
+
+    bool check();
 };
 
 #endif // WRITEJOB_H
diff --git a/lib/isomd5/isomd5.pro b/lib/isomd5/isomd5.pro
new file mode 100644
index 0000000..c84d09f
--- /dev/null
+++ b/lib/isomd5/isomd5.pro
@@ -0,0 +1,13 @@
+TEMPLATE = lib
+
+CONFIG += staticlib
+
+QT += core
+
+DESTDIR = ../
+
+HEADERS += libcheckisomd5.h
+
+SOURCES += libcheckisomd5.cpp
+
+QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.9
diff --git a/lib/isomd5/libcheckisomd5.cpp b/lib/isomd5/libcheckisomd5.cpp
new file mode 100644
index 0000000..cc18ccf
--- /dev/null
+++ b/lib/isomd5/libcheckisomd5.cpp
@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) 2001-2013 Red Hat, Inc.
+ *
+ * Michael Fulbright <msf@redhat.com>
+ * Dustin Kirkland  <dustin.dirkland@gmail.com>
+ *      Added support for checkpoint fragment sums;
+ *      Exits media check as soon as bad fragment md5sum'ed
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#define _LARGEFILE64_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <inttypes.h>
+
+#include <QCryptographicHash>
+
+#include "libcheckisomd5.h"
+
+#ifdef __APPLE__
+#define lseek64 lseek
+#endif
+
+#ifdef _WIN32
+size_t getpagesize () {
+    return 2048; // not really necessary for Windows
+}
+#endif
+
+#define BUFSIZE 32768
+#define SIZE_OFFSET 84
+
+#define MAX(x, y)  ((x > y) ? x : y)
+#define MIN(x, y)  ((x < y) ? x : y)
+
+static int checkmd5sum(int fd, const char *mediasum, checkCallback cb, void *cbdata, long long size) {
+    // Md5 is empty, therefore md5 check not needed
+    if (mediasum[0] == '\0') {
+        return ISOMD5SUM_CHECK_PASSED;
+    }
+    
+    int pagesize = getpagesize();
+    unsigned char *buf_unaligned = (unsigned char *) malloc((BUFSIZE + pagesize) * sizeof(unsigned char));
+    unsigned char *buf = (buf_unaligned + (pagesize - ((uintptr_t) buf_unaligned % pagesize)));
+
+    // Rewind
+    long long offset = lseek64(fd, 0LL, SEEK_SET);
+
+    // Compute md5
+    QCryptographicHash hash(QCryptographicHash::Md5);
+
+    if (cb) {
+        cb(cbdata, 0, size);
+    }
+
+    while (offset < size) {
+        ssize_t nattempt = MIN(size - offset, BUFSIZE);
+
+        ssize_t nread = read(fd, buf, nattempt);
+        if (nread <= 0)
+            break;
+
+        if (nread > nattempt) {
+            nread = nattempt;
+            lseek64(fd, offset + nread, SEEK_SET);
+        }
+
+        hash.addData((const char *) buf, nread);
+
+        offset = offset + nread;
+        if (cb && offset / nread % 256 == 0) {
+            if (cb(cbdata, offset, size)) {
+                free(buf_unaligned);
+                return ISOMD5SUM_CHECK_ABORTED;
+            }
+        }
+    }
+
+    if (cb) {
+        cb(cbdata, size, size);
+    }
+
+    free(buf_unaligned);
+
+    const QByteArray computedsum_bytes = hash.result().toHex();
+    const char *computed_sum = computedsum_bytes.constData();
+
+    const bool sums_match = (memcmp(computed_sum, mediasum, computedsum_bytes.size()) == 0);
+
+    if (sums_match) {
+        return ISOMD5SUM_CHECK_PASSED;
+    } else {
+        return ISOMD5SUM_CHECK_FAILED;
+    }
+}
+
+int mediaCheckFile(const char *file, const char *md5,checkCallback cb, void *cbdata) {
+    int fd;
+
+#ifdef _WIN32
+    fd = open(file, O_RDONLY | O_BINARY);
+#else
+    fd = open(file, O_RDONLY);
+#endif
+
+    if (fd < 0) {
+        return ISOMD5SUM_FILE_NOT_FOUND;
+    }
+
+    // Calculate file size
+    long long size = lseek64(fd, 0L, SEEK_END);
+
+    int rc = checkmd5sum(fd, md5, cb, cbdata, size);
+
+    close(fd);
+
+    return rc;
+}
+
+int mediaCheckFD(int fd, const char *md5, checkCallback cb, void *cbdata) {
+    if (fd < 0) {
+        return ISOMD5SUM_FILE_NOT_FOUND;
+    }
+
+    // NOTE: files that are FD(written to drive) are implicitly always iso's 
+    // Get size
+    int pagesize = getpagesize();
+    unsigned char *buf_unaligned = (unsigned char *) malloc((BUFSIZE + pagesize) * sizeof(unsigned char));
+    unsigned char *buf = (buf_unaligned + (pagesize - ((uintptr_t) buf_unaligned % pagesize)));
+    if (lseek64(fd, (16LL * 2048LL), SEEK_SET) == -1) {
+        free(buf_unaligned);
+        return ISOMD5SUM_CHECK_NOT_FOUND;
+    }
+
+    long long offset = (16LL * 2048LL);
+    for (;1;) {
+        if (read(fd, buf, 2048) <= 0) {
+            free(buf_unaligned);
+            return ISOMD5SUM_CHECK_NOT_FOUND;
+        }
+
+        if (buf[0] == 1) {
+        /* found primary volume descriptor */
+            break;
+        } else if (buf[0] == 255) {
+        /* hit end and didn't find primary volume descriptor */
+            free(buf_unaligned);
+            return ISOMD5SUM_CHECK_NOT_FOUND;
+        }
+        offset += 2048LL;
+    }
+
+    // Get size from pvd
+    long long size = (buf[SIZE_OFFSET] * 0x1000000 + buf[SIZE_OFFSET + 1] * 0x10000 + buf[SIZE_OFFSET + 2] * 0x100 + buf[SIZE_OFFSET + 3]) * 2048LL;
+
+    free(buf_unaligned);
+
+    int rc = checkmd5sum(fd, md5, cb, cbdata, size);
+
+    return rc;
+}
diff --git a/lib/isomd5/libcheckisomd5.h b/lib/isomd5/libcheckisomd5.h
new file mode 100644
index 0000000..6da2015
--- /dev/null
+++ b/lib/isomd5/libcheckisomd5.h
@@ -0,0 +1,18 @@
+#ifndef __LIBCHECKISOMD5_H__
+#define  __LIBCHECKISOMD5_H__
+
+#define ISOMD5SUM_CHECK_PASSED          1
+#define ISOMD5SUM_CHECK_FAILED          0
+#define ISOMD5SUM_CHECK_ABORTED         2
+#define ISOMD5SUM_CHECK_NOT_FOUND       -1
+#define ISOMD5SUM_FILE_NOT_FOUND        -2
+
+/* for non-zero return value, check is aborted */
+typedef int (*checkCallback)(void *, long long offset, long long total);
+
+int mediaCheckFile(const char *iso, const char *md5, checkCallback cb, void *cbdata);
+int mediaCheckFD(int fd, const char *md5, checkCallback cb, void *cbdata);
+int printMD5SUM(char *file);
+
+#endif
+
diff --git a/lib/lib.pro b/lib/lib.pro
new file mode 100644
index 0000000..6160dd5
--- /dev/null
+++ b/lib/lib.pro
@@ -0,0 +1,3 @@
+TEMPLATE = subdirs
+
+SUBDIRS = isomd5
diff --git a/mediawriter.pro b/mediawriter.pro
index 1622b82..cb225fb 100644
--- a/mediawriter.pro
+++ b/mediawriter.pro
@@ -1,3 +1,6 @@
 TEMPLATE = subdirs
 
-SUBDIRS = app helper
+SUBDIRS = lib app helper
+
+app.depends = lib
+helper.depends = lib