我的板子可以通过SD启动，启动正常 ，但是通过SD卡烧入NAND 来启动，即使用下面命令后：
1. Flashing 1st stage to NAND from 2nd stage in SD boot
mmc rescan 0
mw.b 0x81000000 0xFF 0x20000
fatload mmc 0 0x81000000 u-boot.min.nand
nand erase 0x0 0x20000
nand write.i 0x81000000 0x0 0x20000
2 Flashing 2nd stage to NAND from 2nd stage in SD boot
mmc rescan 0
mw.b 0x81000000 0xFF 0x60000
fatload mmc 0 0x81000000 u-boot.bin
nand erase 0x20000 0x60000
nand write.i 0x81000000 0x20000 0x60000
通过NAND FLASH 启不来了，一直停在 Starting application at 0x81000000 ... 打印信息如下：
U-Boot 2010.06 (Oct 18 2015 - 23:17:15)
TI8148-GP rev 3.0
ARM clk: 600MHz
DDR clk: 400MHz
DRAM: 2 GiB
NAND: HW ECC BCH8 Selected
256 MiB
Using default environment
The 2nd stage U-Boot will now be auto-loaded
Please do not interrupt the countdown till TI8148_EVM prompt if 2nd stage is already flashed
Hit any key to stop autoboot: 0
NAND read: device 0 offset 0x100000, size 0x40000
262144 bytes read: OK
## Starting application at 0x81000000 ...
到底是啥原因，我们选的模式是10011
