diff --git a/src/vmm_mad/remotes/lib/lxd/command.rb b/src/vmm_mad/remotes/lib/lxd/command.rb
index 1f64a843db..9437144bfb 100644
--- a/src/vmm_mad/remotes/lib/lxd/command.rb
+++ b/src/vmm_mad/remotes/lib/lxd/command.rb
@@ -32,21 +32,12 @@ module Command
         begin
             fd = lock if block
 
-            Open3.popen3(cmd) {|i, o, e, t|
-                rc = t.value.exitstatus
-
-                stdout = o.read
-                stderr = e.read
-
-                o.close
-                e.close
-            }
-        rescue
+            stdout, stderr, s = Open3.capture3(cmd)
         ensure
             unlock(fd) if block
         end
 
-        [rc, stdout, stderr]
+        [s.exitstatus, stdout, stderr]
     end
 
     def self.execute_once(cmd, lock)
diff --git a/src/vmm_mad/remotes/lib/lxd/mapper/qcow2.rb b/src/vmm_mad/remotes/lib/lxd/mapper/qcow2.rb
index 54e51b2927..a1d706c7f8 100644
--- a/src/vmm_mad/remotes/lib/lxd/mapper/qcow2.rb
+++ b/src/vmm_mad/remotes/lib/lxd/mapper/qcow2.rb
@@ -42,9 +42,10 @@ class Qcow2Mapper < Mapper
             return
         end
 
+        # TODO: improve wait condition
         sleep 5 # wait for parts to come out
 
-        show_parts(device) unless part?(device)
+        show_parts(device) unless parts_on?(device)
 
         device
     end
@@ -56,7 +57,6 @@ class Qcow2Mapper < Mapper
         #
         # TODO: avoid using if kpartx was not used
         hide_parts(device)
-        
         cmd = "#{COMMANDS[:nbd]} -d #{device}"
 
         rc, _out, err = Command.execute(cmd, false)
@@ -69,9 +69,10 @@ class Qcow2Mapper < Mapper
 
     private
 
-    def part?(device)
+    # Returns true if device has mapped partitions
+    def parts_on?(device)
         partitions = lsblk(device)
-        return true unless partitions[0]['type'] == 'part'
+        return true if partitions[0]['type'] == 'part'
 
         false
     end
@@ -84,13 +85,15 @@ class Qcow2Mapper < Mapper
         action_parts(device, '-d')
     end
 
+    # Runs kpartx vs a device with required flags as arguments
     def action_parts(device, action)
         cmd = "#{COMMANDS[:kpartx]} #{action} #{device}"
         rc, _out, err = Command.execute(cmd, false)
 
-        return unless rc.zero?
+        return true if rc.zero?
 
         OpenNebula.log_error("#{__method__}: #{err}")
+        false
     end
 
     def nbd_device
diff --git a/src/vmm_mad/remotes/lib/lxd/mapper/rbd.rb b/src/vmm_mad/remotes/lib/lxd/mapper/rbd.rb
index b3fbd55f89..d99ec413b7 100644
--- a/src/vmm_mad/remotes/lib/lxd/mapper/rbd.rb
+++ b/src/vmm_mad/remotes/lib/lxd/mapper/rbd.rb
@@ -34,6 +34,9 @@ class RBDMapper < Mapper
 
         rc, out, err = Command.execute(cmd, false)
 
+        # TODO: improve wait condition
+        sleep 5 # wait for partition table
+
         return out.chomp if rc.zero?
 
         OpenNebula.log_error("#{__method__}: #{err}")