diff --git a/tools/mkimage-iso-bios/make-iso b/tools/mkimage-iso-bios/make-iso
index 6c4582c96..7551b91f7 100755
--- a/tools/mkimage-iso-bios/make-iso
+++ b/tools/mkimage-iso-bios/make-iso
@@ -5,22 +5,17 @@ set -e
 mkdir -p /tmp/iso
 cd /tmp/iso
 
-# input is a tarball of kernel and initrd.img on stdin
+# input is a tarball of filesystem on stdin with kernel in /boot
 # output is an iso on stdout
 
 # extract. BSD tar auto recognises compression, unlike GNU tar
 # only if stdin is a tty, if so need files volume mounted...
 [ -t 0 ] || bsdtar xzf -
 
-INITRD="$(find . -name '*.img')"
-KERNEL="$(find . -name kernel -or -name '*bzImage')"
-CMDLINE="$*"
-
-[ "$KERNEL" = "kernel" ] || mv "$KERNEL" kernel
-[ "$INITRD" = "initrd.img" ] || mv "$INITRD" initrd.img
-
-# clean up subdirectories
-find . -mindepth 1 -maxdepth 1 -type d | xargs rm -rf
+CMDLINE="$(cat boot/cmdline)"
+# if no root= root device specified, assume /dev/sr0 ie first CD drive
+echo "${CMDLINE}" | grep -q 'root=' || CMDLINE="${CMDLINE} root=/dev/sr0"
+rm boot/cmdline
 
 mkdir -p isolinux
 cp /usr/share/syslinux/isolinux.bin ./isolinux/
@@ -28,8 +23,7 @@ cp /usr/share/syslinux/ldlinux.c32 ./isolinux/
 
 CFG="DEFAULT linux
 LABEL linux
-    KERNEL /kernel
-    INITRD /initrd.img
+    KERNEL /boot/kernel
     APPEND ${CMDLINE}
 "
 
@@ -39,6 +33,7 @@ genisoimage -o ../linuxkit-bios.iso -l -J -R \
                 -c isolinux/boot.cat  \
                 -b isolinux/isolinux.bin \
                    -no-emul-boot -boot-load-size 4 -boot-info-table \
+		-joliet-long -input-charset utf8 \
                 -V LinuxKit .
 
 isohybrid ../linuxkit-bios.iso