Index: /trunk/src/VBox/Additions/linux/installer/vboxadd.sh
===================================================================
--- /trunk/src/VBox/Additions/linux/installer/vboxadd.sh	(revision 25686)
+++ /trunk/src/VBox/Additions/linux/installer/vboxadd.sh	(revision 25687)
@@ -39,4 +39,9 @@
 BUILDVBOXVIDEO=`/bin/ls /usr/src/vboxvideo*/build_in_tmp 2>/dev/null|cut -d' ' -f1`
 LOG="/var/log/vboxadd-install.log"
+MODPROBE=/sbin/modprobe
+
+if $MODPROBE -c | grep -q '^allow_unsupported_modules  *0'; then
+  MODPROBE="$MODPROBE --allow-unsupported-modules"
+fi
 
 # Check architecture
@@ -205,5 +210,5 @@
         }
 
-        modprobe vboxguest >/dev/null 2>&1 || {
+        $MODPROBE vboxguest >/dev/null 2>&1 || {
             fail "modprobe vboxguest failed"
         }
@@ -257,5 +262,5 @@
     if [ -n "$BUILDVBOXVFS" ]; then
         running_vboxvfs || {
-            modprobe vboxvfs > /dev/null 2>&1 || {
+            $MODPROBE vboxvfs > /dev/null 2>&1 || {
                 if dmesg | grep "vboxConnect failed" > /dev/null 2>&1; then
                     fail_msg
Index: /trunk/src/VBox/Installer/linux/vboxdrv.sh.in
===================================================================
--- /trunk/src/VBox/Installer/linux/vboxdrv.sh.in	(revision 25686)
+++ /trunk/src/VBox/Installer/linux/vboxdrv.sh.in	(revision 25687)
@@ -37,4 +37,9 @@
 NOLSB=%NOLSB%
 DEBIAN=%DEBIAN%
+MODPROBE=/sbin/modprobe
+
+if $MODPROBE -c | grep -q '^allow_unsupported_modules  *0'; then
+  MODPROBE="$MODPROBE --allow-unsupported-modules"
+fi
 
 [ -f /lib/lsb/init-functions ] || NOLSB=yes
@@ -167,5 +172,5 @@
           echo 2 > /proc/sys/kernel/perf_counter_paranoid 
         fi
-        if ! modprobe vboxdrv > /dev/null 2>&1; then
+        if ! $MODPROBE vboxdrv > /dev/null 2>&1; then
             failure "modprobe vboxdrv failed. Please use 'dmesg' to find out why"
         fi
@@ -199,8 +204,8 @@
         failure "Cannot change owner $GROUPNAME for device $DEVICE"
     fi
-    if ! modprobe vboxnetflt > /dev/null 2>&1; then
+    if ! $MODPROBE vboxnetflt > /dev/null 2>&1; then
         failure "modprobe vboxnetflt failed. Please use 'dmesg' to find out why"
     fi
-    if ! modprobe vboxnetadp > /dev/null 2>&1; then
+    if ! $MODPROBE vboxnetadp > /dev/null 2>&1; then
         failure "modprobe vboxnetadp failed. Please use 'dmesg' to find out why"
     fi