kernel panic on mounting romfs

I am running embedded uClibc on a 5208 Coldfire board. NFS mounting of
the filesystem works, but not when it has to boot entirely out from
flash.

Any help is appreciated.

uClinux/COLDFIRE(m520x)
COLDFIRE port done by Greg Ungerer, [email]gerg@snapgear.com[/email]
Flat model support (C) 1998,1999 Kenneth Albanowski, D. Jeff Dionne
Built 1 zonelists. Total pages: 2032
Kernel command line: rootfstype=romfs
PID hash table entries: 32 (order: 5, 128 bytes)
Dentry cache hash table entries: 1024 (order: 0, 4096 bytes)
Inode-cache hash table entries: 1024 (order: 0, 4096 bytes)
Memory available: 5484k/8192k RAM, (1342k kernel code, 180k data)
Mount-cache hash table entries: 512
NET: Registered protocol family 16
NET: Registered protocol family 2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 1024 (order: 0, 4096 bytes)
TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
TCP: Hash tables configured (established 1024 bind 1024)
TCP reno registered
JFFS2 version 2.2. (NAND) (C) 2001-2006 Red Hat, Inc.
io scheduler noop registered
io scheduler cfq registered (default)
ColdFire internal UART serial driver version 1.00
ttyS0 at 0xfc060000 (irq = 90) is a builtin ColdFire UART
ttyS1 at 0xfc064000 (irq = 91) is a builtin ColdFire UART
ttyS2 at 0xfc068000 (irq = 92) is a builtin ColdFire UART
FEC ENET Version 0.2
fec: PHY @ 0x0, ID 0x0143bc31 -- unknown PHY!
eth0: ethernet 00:cf:52:08:cf:01
m520xevb flash probe(0x0,800000,2): 800000 at 0
Number of erase regions: 2
Primary Vendor Command Set: 0002 (AMD/Fujitsu Standard)
Primary Algorithm Table at 0040
Alternative Vendor Command Set: 0000 (None)
No Alternate Algorithm Table
Vcc Minimum: 2.7 V
Vcc Maximum: 3.6 V
Vpp Minimum: 11.5 V
Vpp Maximum: 12.5 V
Typical byte/word write timeout: 16 µs
Maximum byte/word write timeout: 256 µs
Full buffer write not supported
Typical block erase timeout: 1024 ms
Maximum block erase timeout: 8192 ms
Chip erase not supported
Device size: 0x800000 bytes (8 MiB)
Flash Device Interface description: 0x0002
- supports x8 and x16 via BYTE# with asynchronous interface
Max. bytes in buffer write: 0x10
Number of Erase Block Regions: 2
Erase Region #0: BlockSize 0x2000 bytes, 8 blocks
Erase Region #1: BlockSize 0x10000 bytes, 127 blocks
ST M29W640FB flash device (8MB): Found 1 x16 devices at 0x0 in 16-bit
bank
Amd/Fujitsu Extended Query Table at 0x0040
number of CFI chips: 1
cfi_cmdset_0002: Disabling erase-suspend-program due to code
brokenness.
Creating 2 MTD partitions on "ST M29W640FB flash device (8MB)":
0x00000000-0x00040000 : "dBUG (256K)"
mtd: Giving out device 0 to dBUG (256K)
0x00040000-0x00800000 : "User FS (1792K)"
mtd: Giving out device 1 to User FS (1792K)
m520xevb ram probe(0x4019cdac,f2000,4): f2000 at 4019cdac
Creating 1 MTD partitions on "RAM":
0x00000000-0x000f2000 : "Romfs"
mtd: Giving out device 2 to Romfs
TCP cubic registered
NET: Registered protocol family 1
NET: Registered protocol family 17
VFS: Cannot open root device "<NULL>" or unknown-block(31,2)
Please append a correct "root=" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-
block(31,2)