U disk burning system and application under uboot

U disk burning system and application under uboot

今天，现场出现了一台桩，启动的时候，uboot提示如下：
CPU: NUC972
DRAM:  64 MiB
NAND:  128 MiB
MMC:   mmc: 0
In:    serial
Out:   serial
Err:   serial
Net:   emac
Hit any key to stop autoboot:  0 

Loading from nand0, offset 0x200000
** Unknown image type
Wrong Image Format for bootm command
ERROR: can't get kernel image!

以上就是内核损坏了，现场只有U盘口，所以以下就uboot模式下，烧写系统及应用程序

## nand storage partition

我们需要烧写的几个文件及区域如下：
   文件名称        起始地址     大小
1：linux-kernel  0x200000 	2.5M左右
2：root-fs		0x700000    12M左右
3：app	        0x1B00000   3M左右

Burning commands and processes

The detailed process of burning the kernel is as follows:

U-Boot> usb start
(Re)start USB...
USB0:   USB EHCI 0.95
scanning bus 0 for devices... 2 USB Device(s) found
       scanning usb for storage devices... 1 Storage Device(s) found
U-Boot> usb dev

USB device 0: Vendor: USB      Rev: 1100 Prod: Flash Disk      
            Type: Removable Hard Disk
            Capacity: 7681.0 MB = 7.5 GB (15730688 x 512)
U-Boot> fatls usb 0
            system volume information/
      128   autorun.inf 
            boot/
   413738   bootmgr 
  1541648   bootmgr.efi 
            efi/
    74184   setup.exe 
            sources/
            support/
            °
            a8_tcu/
            xrd_tft/
            ui/
  2400064   970uimage 

5 file(s), 9 dir(s)

U-Boot> fatload usb 0 0x3000000 970uimage
reading 970uimage
2400064 bytes read in 136 ms (16.8 MiB/s)
U-Boot> nand erase 0x200000 0x400000

NAND erase: device 0 offset 0x200000, size 0x400000
Erasing at 0x5e0000 -- 100% complete.
OK
U-Boot> nand write 0x3000000 0x200000 0x400000

NAND write: device 0 offset 0x200000, size 0x400000
 4194304 bytes written: OK

Complete command and instructions

usb start			//启动usb
usb dev				//查看usb设备
fatls usb 0			//查看usb内的文件
fatload usb 0 0x3000000 uImage			//将指定文件加载到内存中
nand erase 0x200000 0x400000			//擦除nand上指定位置的数据
nand write 0x3000000 0x200000 0x400000	//将文件烧写到nand的指定位置

mw.b 0x3000000 0xff 0x1400000			//清除内存指定位置上的数据
fatload usb 0 0x3000000 rootfs.cramfs	//加载usb上文件到内存上
nand erase 0x700000 0x1400000			//清除nand上指定位置，指定大小空间
nand write 0x3000000 0x700000 0x1400000	//将内存上文件写到nand指定位置

//同上，写app区数据
mw.b 0x3000000 0xff 0x500000
fatload usb 0 0x3000000 cl5899_tcu_app.img
nand erase 0x1B00000 0x500000
nand write 0x3000000 0x1B00000 0x500000