diff --git a/rpi23-gen-image.sh b/rpi23-gen-image.sh
index f8e65fb..7a0adb3 100755
--- a/rpi23-gen-image.sh
+++ b/rpi23-gen-image.sh
@@ -556,8 +556,8 @@ ROOT_OFFSET=$(expr ${TABLE_SECTORS} + ${FRMW_SECTORS})
 
 # The root partition is EXT4
 # This means more space than the actual used space of the chroot is used.
-# As overhead for journaling and reserved blocks 25% are added.
-ROOT_SECTORS=$(expr $(expr ${CHROOT_SIZE} + ${CHROOT_SIZE} \/ 100 \* 25) \* 1024 \/ 512)
+# As overhead for journaling and reserved blocks 35% are added.
+ROOT_SECTORS=$(expr $(expr ${CHROOT_SIZE} + ${CHROOT_SIZE} \/ 100 \* 35) \* 1024 \/ 512)
 
 # Calculate required image size in 512 Byte sectors
 IMAGE_SECTORS=$(expr ${TABLE_SECTORS} + ${FRMW_SECTORS} + ${ROOT_SECTORS})