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1. Copy u-boot image to RAM area.
-2. Probe SPI device.
- => sf probe 0
+2. Probe SPI device.
+ => sf probe 0
8192 KiB M25P64 at 0:0 is now current device
3. Erase SPI ROM.
- => sf erase 0 80000
+ => sf erase 0 80000
4. Write u-boot image to SPI ROM.
=> sf write 0x89000000 0 80000
-