I have got an problem i just managed to extract the arch rootfs to my 16gb micro sd card and i created an u-boot menu item file with following in it

ITEM_NAME="Arch Linux ARM (SD Card)"
ITEM_KERNEL="/boot/uImage"
ITEM_DEVICE="${EXT_CARD}p1"
ITEM_FSTYPE="ext4"
ITEM_OMAPATAG="1"
ITEM_CMDLINE="root=/dev/mmcblk0p1 rootwait
init=/bin/systemd omapfb.vram=0:3M,1:3M,2:3M quiet"

now when i use the u-boot-update-bootmenu command from xtem in root it give back then following

configuration file: /etc/bootmenu.d/20-archlinux.item
'rror: unkown file system 'ext4

what can i do to correct this and be able to run arch linux on my n900

thanx for the advance