diff --git a/target/linux/bcm27xx/image/gen_rpi_sdcard_img.sh b/target/linux/bcm27xx/image/gen_rpi_sdcard_img.sh
index 8d33e4f54c..492347a61e 100755
--- a/target/linux/bcm27xx/image/gen_rpi_sdcard_img.sh
+++ b/target/linux/bcm27xx/image/gen_rpi_sdcard_img.sh
@@ -24,5 +24,34 @@ set $(ptgen -o $OUTPUT -h $head -s $sect -l $align -t $kernel_type -p ${BOOTFSSI
 BOOTOFFSET="$(($1 / 512))"
 ROOTFSOFFSET="$(($3 / 512))"
 
+# In most cases, the rootfs image size is smaller than the total space
+# available in the rootfs. OpenWrt will use the remaining space for storing
+# the fs backing the overlayfs which holds configuration changes etc.
+# To avoid that OpenWrt incorrectly detects a filesystem in the case
+# there is remaining data from a previous installation, we need to clear
+# the first N bytes directly after the rootfs image, to make sure
+# that any initial bytes that are or look like fs superblocks are cleared
+# out. 
+ROOTFSSIZE="$(($4 / 512))"
+ROOTFSIMGSIZE="$((($(wc -c < $ROOTFS) + 511) / 512))"
+ROOTFSPADDINGSIZE="$(($ROOTFSSIZE - $ROOTFSIMGSIZE))"
+ROOTFSPADDINGOFFSET="$(($ROOTFSOFFSET + $ROOTFSIMGSIZE))"
+
+# Reduce padding to max 1MB, which is enough to clear out any superblocks
+# of previous file-systems or any data that might look like fs superblocks.
+if [ "$ROOTFSPADDINGSIZE" -gt 2048 ]; then
+  ROOTFSPADDINGSIZE="2048"
+fi
+
+# Write the bootfs.
 dd bs=512 if="$BOOTFS" of="$OUTPUT" seek="$BOOTOFFSET" conv=notrunc
-dd bs=512 if="$ROOTFS" of="$OUTPUT" seek="$ROOTFSOFFSET" conv=notrunc
+
+# Write the rootfs.
+# The `sync` is important, as in case $ROOTFS is not a multiple of bs, it will
+# assure that remaining bytes are set to 0x00.
+dd bs=512 if="$ROOTFS" of="$OUTPUT" seek="$ROOTFSOFFSET" conv=notrunc,sync
+
+# Add padding after rootfs.
+if [ "$ROOTFSPADDINGSIZE" -gt 0 ]; then
+  dd bs=512 if=/dev/zero of="$OUTPUT" seek="$ROOTFSPADDINGOFFSET" count="$ROOTFSPADDINGSIZE" conv=notrunc
+fi