Can't create rootfs

1. why the uclinux boot twice , and the first boot is diffrent from the second one

2. why it can't mount the romfs , i had programe the romfs into the flash from address 0x200000

3. i only have 4Mbytes flash memory , why microtronix said make the romfs from 0x200000 to 0x800000.

the boot message is below:

nios2-terminal: Warning: The JTAG cable you are using is not supported for Nios

nios2-terminal: II systems. You may experience intermittent JTAG communication

nios2-terminal: failures with this cable. Please use a USB Blaster revision B

nios2-terminal: cable or another supported cable. Please refer to the file

nios2-terminal: errata.txt included in the Nios II development kit documents

nios2-terminal: directory for more information.

nios2-terminal: connected to hardware target using JTAG UART on cable

nios2-terminal: "ByteBlasterII [LPT1]", device 1, instance 0

nios2-terminal: (Use the IDE stop button or Ctrl-C to terminate)

Linux version 2.6.11-uc0 (user@USER-E3A02B44B7) (gcc version 3.4.1 (Altera Nios

II 5.0 b73))# 19 Sat Oct 22 14:50:14 2005

uClinux/Nios II

Altera Nios II support © 2004 Microtronix Datacom Ltd.

Built 1 zonelists

Kernel command line: root=/dev/mtdblock0 ro

PID hash table entries: 64 (order: 6, 1024 bytes)

Dentry cache hash table entries: 2048 (order: 1, 8192 bytes)

Inode-cache hash table entries: 1024 (order: 0, 4096 bytes)

Memory available: 6364k/8192k RAM, 0k/0k ROM (1419k kernel code, 289k data)

Mount-cache hash table entries: 512 (order: 0, 4096 bytes)

NET: Registered protocol family 16

Serial: JTAG UART driver $Revision: 1.4 $

ttyJ0 at MMIO 0x80401880 (irq = 0) is a jtag_uart

io scheduler noop registered

io scheduler anticipatory registered

io scheduler deadline registered

io scheduler cfq registered

RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize

Microtronix map: Found 2 x8 devices at 0x0 in 16-bit bank

Intel/Sharp Extended Query Table at 0x0031

Using buffer write method

cfi_cmdset_0001: Erase suspend on write enabled

cmdlinepart partition parsing not available

RedBoot partition parsing not available

Using Microtronix development partition definition

Creating 2 MTD partitions on "Microtronix map":

0x00200000-0x00800000 : "romfs"

0x00000000-0x00200000 : "loader/kernel"

NET: Registered protocol family 2

IP: routing cache hash table of 512 buckets, 4Kbytes

TCP established hash table entries: 512 (order: 0, 4096 bytes)

TCP bind hash table entries: 512 (order: -1, 2048 bytes)

TCP: Hash tables configured (established 512 bind 512)

NET: Registered protocol family 1

NET: Registered protocol family 17

Linux version 2.6.11-uc0 (user@USER-E3A02B44B7) (gcc version 3.4.1 (Altera Nios

II 5.0 b73))# 19 Sat Oct 22 14:50:14 2005

uClinux/Nios II

Altera Nios II support © 2004 Microtronix Datacom Ltd.

Built 1 zonelists

Kernel command line: root=/dev/mtdblock0 ro

PID hash table entries: 128 (order: 7, 2048 bytes)

Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)

Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)

Memory available: 6352k/8192k RAM, 0k/0k ROM (1419k kernel code, 289k data)

Mount-cache hash table entries: 512 (order: 0, 4096 bytes)

Kernel panic - not syncing: Can't create rootfs