> halt
target state: halted
target halted in ARM state due to debug-request, current mode: Abort
cpsr: 0x400001d7 pc: 0x00000010
> nand probe 0
unknown NAND flash device found, manufacturer id: 0x18 device id: 0x18
in procedure nand
上述提示错误信息为找不到NAND flash 器材。解决办法如下：：：
> arm mcr 15 0 1 0 0 0
> step 0
target state: halted
target halted in ARM state due to single-step, current mode: Abort
cpsr: 0x400001d7 pc: 0x00000004
> nand probe 0
unknown NAND flash device found, manufacturer id: 0x0c device id: 0x0c
in procedure nand
> step 1
target state: halted
target halted in ARM state due to single-step, current mode: Abort
cpsr: 0x400001d7 pc: 0x00000004
> step 4
target state: halted
target halted in ARM state due to single-step, current mode: Abort
cpsr: 0x400001d7 pc: 0x00000008
> step 8
target state: halted
target halted in ARM state due to single-step, current mode: Abort
cpsr: 0x400001d7 pc: 0x0000000c
> step 88
target state: halted
target halted in ARM state due to single-step, current mode: Abort
cpsr: 0x400001d7 pc: 0x000000b0
> step 999
target state: halted
target halted in ARM state due to single-step, current mode: Abort
cpsr: 0x400001d7 pc: 0x00000410
> step 111111
target state: halted
target halted in ARM state due to single-step, current mode: Abort
cpsr: 0x400001d7 pc: 0x0001b208
> nand probe 0
NAND flash device K9GAG08 2GB NAND 3.3V x8 MLC 2b/cell (Samsung) found
> nand erase 0 0 0x100000
s3c2440_read_block_data: reading data: 0x8a2f268, 0xbfdc5efa, 6
erased blocks 0 to 1 on NAND flash device #0 K9GAG08 2GB NAND 3.3V x8 MLC 2b/cell
这种指令的意图是要封闭MMU，
关掉后才干拜访里边的寄存器
