diff --git a/src/app/rpmostree-builtin-status.c b/src/app/rpmostree-builtin-status.c
index fb959728..b9d4cd36 100644
--- a/src/app/rpmostree-builtin-status.c
+++ b/src/app/rpmostree-builtin-status.c
@@ -480,6 +480,7 @@ print_one_deployment (RPMOSTreeSysroot *sysroot_proxy,
       g_autofree char *canonrefspec = rpmostree_refspec_to_string (refspectype, refspec_data);
       switch (refspectype)
         {
+        case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
         case RPMOSTREE_REFSPEC_TYPE_OSTREE:
           {
             g_print ("%s", canonrefspec);
diff --git a/src/daemon/rpmostree-sysroot-upgrader.c b/src/daemon/rpmostree-sysroot-upgrader.c
index d296a7bd..ecaa37d8 100644
--- a/src/daemon/rpmostree-sysroot-upgrader.c
+++ b/src/daemon/rpmostree-sysroot-upgrader.c
@@ -397,6 +397,7 @@ rpmostree_sysroot_upgrader_pull_base (RpmOstreeSysrootUpgrader  *self,
 
   switch (refspec_type)
     {
+    case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
     case RPMOSTREE_REFSPEC_TYPE_OSTREE:
       {
         g_autofree char *origin_remote = NULL;
diff --git a/src/daemon/rpmostreed-deployment-utils.c b/src/daemon/rpmostreed-deployment-utils.c
index 78bd6826..1648cbfb 100644
--- a/src/daemon/rpmostreed-deployment-utils.c
+++ b/src/daemon/rpmostreed-deployment-utils.c
@@ -303,6 +303,9 @@ rpmostreed_deployment_generate_variant (OstreeSysroot *sysroot,
 
   switch (refspec_type)
     {
+    case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
+      /* Nothing to do here */
+      break;
     case RPMOSTREE_REFSPEC_TYPE_OSTREE:
       {
         if (!variant_add_remote_status (repo, refspec, base_checksum, &dict, error))
@@ -424,7 +427,9 @@ add_all_commit_details_to_vardict (OstreeDeployment *deployment,
         return FALSE;
       refspec = refspec_remainder;
     }
-  refspec_is_ostree = (refspec_type == RPMOSTREE_REFSPEC_TYPE_OSTREE);
+  refspec_is_ostree = refspec_type == RPMOSTREE_REFSPEC_TYPE_OSTREE;
+  if (refspec_type == RPMOSTREE_REFSPEC_TYPE_CHECKSUM && !commit)
+    checksum = refspec;
 
   g_assert (refspec);
 
@@ -962,10 +967,14 @@ rpmostreed_update_generate_variant (OstreeDeployment  *booted_deployment,
       return FALSE;
 
     /* we don't support rojig-based origins yet */
-    if (refspectype != RPMOSTREE_REFSPEC_TYPE_OSTREE)
+    switch (refspectype)
       {
+      case RPMOSTREE_REFSPEC_TYPE_ROJIG:
         *out_update = NULL;
         return TRUE; /* NB: early return */
+      case RPMOSTREE_REFSPEC_TYPE_OSTREE:
+      case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
+        break;
       }
 
     /* just skip over "ostree://" so we can talk with libostree without thinking about it */
diff --git a/src/daemon/rpmostreed-transaction-types.c b/src/daemon/rpmostreed-transaction-types.c
index ddc944d5..d3d503e0 100644
--- a/src/daemon/rpmostreed-transaction-types.c
+++ b/src/daemon/rpmostreed-transaction-types.c
@@ -76,6 +76,7 @@ change_origin_refspec (OstreeSysroot *sysroot,
           return TRUE;
         }
     case RPMOSTREE_REFSPEC_TYPE_OSTREE:
+    case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
       break;
     }
 
@@ -137,6 +138,9 @@ apply_revision_override (RpmostreedTransaction    *transaction,
   RpmOstreeRefspecType refspectype;
   rpmostree_origin_classify_refspec (origin, &refspectype, NULL);
 
+  if (refspectype == RPMOSTREE_REFSPEC_TYPE_CHECKSUM)
+    return glnx_throw (error, "Cannot look up version while pinned to commit");
+
   g_autofree char *checksum = NULL;
   g_autofree char *version = NULL;
   if (!rpmostreed_parse_revision (revision, &checksum, &version, error))
@@ -163,6 +167,8 @@ apply_revision_override (RpmostreedTransaction    *transaction,
           /* This case we'll look up later */
           rpmostree_origin_set_rojig_version (origin, version);
           break;
+        case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
+          g_assert_not_reached ();  /* Handled above */
         }
     }
   else
@@ -182,6 +188,8 @@ apply_revision_override (RpmostreedTransaction    *transaction,
            * on.
            */
           break;
+        case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
+          g_assert_not_reached ();  /* Handled above */
         }
 
       rpmostree_origin_set_override_commit (origin, checksum, version);
@@ -1135,6 +1143,10 @@ deploy_transaction_execute (RpmostreedTransaction *transaction,
       changed = TRUE;
     }
 
+  /* Past this point we've computed the origin */
+  RpmOstreeRefspecType refspec_type;
+  rpmostree_origin_classify_refspec (origin, &refspec_type, NULL);
+
   if (download_metadata_only)
     {
       /* We have to short-circuit the usual path here; we already downloaded the ostree
@@ -1246,7 +1258,10 @@ deploy_transaction_execute (RpmostreedTransaction *transaction,
     }
   else
     {
-      if (!self->revision)
+      if (refspec_type == RPMOSTREE_REFSPEC_TYPE_CHECKSUM
+          && layering_type < RPMOSTREE_SYSROOT_UPGRADER_LAYERING_RPMMD_REPOS)
+        rpmostree_output_message ("Pinned to commit; no upgrade available");
+      else if (!self->revision)
         rpmostree_output_message ("No upgrade available.");
       else
         rpmostree_output_message ("No change.");
diff --git a/src/libpriv/rpmostree-core.c b/src/libpriv/rpmostree-core.c
index fb715d66..68ac8871 100644
--- a/src/libpriv/rpmostree-core.c
+++ b/src/libpriv/rpmostree-core.c
@@ -50,7 +50,9 @@
 static OstreeRepo * get_pkgcache_repo (RpmOstreeContext *self);
 
 /* Given a string, look for ostree:// or rojig:// prefix and
- * return its type and the remainder of the string.
+ * return its type and the remainder of the string.  Note
+ * that ostree:// can be either a refspec (TYPE_OSTREE) or
+ * a bare commit (TYPE_COMMIT).
  */
 gboolean
 rpmostree_refspec_classify (const char *refspec,
@@ -58,29 +60,28 @@ rpmostree_refspec_classify (const char *refspec,
                             const char **out_remainder,
                             GError     **error)
 {
-  if (g_str_has_prefix (refspec, RPMOSTREE_REFSPEC_OSTREE_PREFIX))
-    {
-      *out_type = RPMOSTREE_REFSPEC_TYPE_OSTREE;
-      if (out_remainder)
-        *out_remainder = refspec + strlen (RPMOSTREE_REFSPEC_OSTREE_PREFIX);
-      return TRUE;
-    }
-  else if (g_str_has_prefix (refspec, RPMOSTREE_REFSPEC_ROJIG_PREFIX))
+  if (g_str_has_prefix (refspec, RPMOSTREE_REFSPEC_ROJIG_PREFIX))
     {
       *out_type = RPMOSTREE_REFSPEC_TYPE_ROJIG;
       if (out_remainder)
         *out_remainder = refspec + strlen (RPMOSTREE_REFSPEC_ROJIG_PREFIX);
       return TRUE;
     }
+  /* Add any other prefixes here */
 
-  /* Fallback case when we have no explicit prefix - treat this as ostree://
-   * for compatibility.  In the future we may do some error checking here,
-   * i.e. trying to parse the refspec.
-   */
-  *out_type = RPMOSTREE_REFSPEC_TYPE_OSTREE;
+  /* For compatibility, fall back to ostree:// when we have no prefix. */
+  const char *remainder;
+  if (g_str_has_prefix (refspec, RPMOSTREE_REFSPEC_OSTREE_PREFIX))
+    remainder = refspec + strlen (RPMOSTREE_REFSPEC_OSTREE_PREFIX);
+  else
+    remainder = refspec;
+
+  if (ostree_validate_checksum_string (remainder, NULL))
+    *out_type = RPMOSTREE_REFSPEC_TYPE_CHECKSUM;
+  else
+    *out_type = RPMOSTREE_REFSPEC_TYPE_OSTREE;
   if (out_remainder)
-    *out_remainder = refspec;
-
+    *out_remainder = remainder;
   return TRUE;
 }
 
@@ -92,6 +93,7 @@ rpmostree_refspec_to_string (RpmOstreeRefspecType  reftype,
   switch (reftype)
     {
     case RPMOSTREE_REFSPEC_TYPE_OSTREE:
+    case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
       prefix = RPMOSTREE_REFSPEC_OSTREE_PREFIX;
       break;
     case RPMOSTREE_REFSPEC_TYPE_ROJIG:
diff --git a/src/libpriv/rpmostree-core.h b/src/libpriv/rpmostree-core.h
index 83e880d5..63bf5db7 100644
--- a/src/libpriv/rpmostree-core.h
+++ b/src/libpriv/rpmostree-core.h
@@ -51,6 +51,7 @@ G_DECLARE_FINAL_TYPE (RpmOstreeTreespec, rpmostree_treespec, RPMOSTREE, TREESPEC
 typedef enum {
   RPMOSTREE_REFSPEC_TYPE_OSTREE,
   RPMOSTREE_REFSPEC_TYPE_ROJIG,
+  RPMOSTREE_REFSPEC_TYPE_CHECKSUM,
 } RpmOstreeRefspecType;
 
 #define RPMOSTREE_REFSPEC_OSTREE_PREFIX "ostree://"
diff --git a/src/libpriv/rpmostree-origin.c b/src/libpriv/rpmostree-origin.c
index 6c8a5005..c2b1a144 100644
--- a/src/libpriv/rpmostree-origin.c
+++ b/src/libpriv/rpmostree-origin.c
@@ -125,7 +125,8 @@ rpmostree_origin_parse_keyfile (GKeyFile         *origin,
     return glnx_null_throw (error, "Duplicate origin/refspec and origin/rojig in deployment origin");
   else if (refspec)
     {
-      ret->refspec_type = RPMOSTREE_REFSPEC_TYPE_OSTREE;
+      if (!rpmostree_refspec_classify (refspec, &ret->refspec_type, NULL, error))
+        return FALSE;
       /* Note the lack of a prefix here so that code that just calls
        * rpmostree_origin_get_refspec() in the ostree:// case
        * sees it without the prefix for compatibility.
@@ -206,6 +207,7 @@ rpmostree_origin_get_full_refspec (RpmOstreeOrigin *origin,
   switch (origin->refspec_type)
     {
     case RPMOSTREE_REFSPEC_TYPE_OSTREE:
+    case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
       return g_strdup (origin->cached_refspec);
     case RPMOSTREE_REFSPEC_TYPE_ROJIG:
       return g_strconcat (RPMOSTREE_REFSPEC_ROJIG_PREFIX, origin->cached_refspec, NULL);
@@ -485,6 +487,7 @@ rpmostree_origin_set_rebase (RpmOstreeOrigin *origin,
   origin->cached_refspec = g_strdup (refspecdata);
   switch (origin->refspec_type)
     {
+    case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
     case RPMOSTREE_REFSPEC_TYPE_OSTREE:
       {
         g_key_file_remove_key (origin->kf, "origin", "rojig", NULL);
@@ -577,6 +580,7 @@ update_keyfile_pkgs_from_cache (RpmOstreeOrigin *origin,
       switch (origin->refspec_type)
         {
         case RPMOSTREE_REFSPEC_TYPE_OSTREE:
+        case RPMOSTREE_REFSPEC_TYPE_CHECKSUM:
           {
             g_key_file_set_value (origin->kf, "origin", "baserefspec",
                                   origin->cached_refspec);
diff --git a/tests/vmcheck/test-pinned-commit.sh b/tests/vmcheck/test-pinned-commit.sh
new file mode 100755
index 00000000..f0f74d76
--- /dev/null
+++ b/tests/vmcheck/test-pinned-commit.sh
@@ -0,0 +1,40 @@
+#!/bin/bash
+#
+# Copyright (C) 2018 Red Hat, Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2 of the License, or (at your option) any later version.
+#
+# This library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the
+# Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+# Boston, MA 02111-1307, USA.
+
+set -euo pipefail
+
+. ${commondir}/libtest.sh
+. ${commondir}/libvm.sh
+
+set -x
+
+checksum=$(vm_get_booted_csum)
+vm_rpmostree rebase :${checksum}
+vm_assert_status_jq ".deployments[0][\"origin\"] == \"${checksum}\""
+vm_rpmostree status > status.txt
+assert_file_has_content status.txt '^  ostree://'${checksum}
+echo "ok pin to commit"
+
+vm_rpmostree upgrade >out.txt
+assert_file_has_content out.txt 'Pinned to commit; no upgrade available'
+if vm_rpmostree deploy 42 2>err.txt; then
+    fatal "deployed version from commit?"
+fi
+assert_file_has_content err.txt 'Cannot look up version while pinned to commit'
+echo "ok cmds"