U-Boot modification for MT7621 Devices

Forked from pinney/MT7621-u-boot-mod @ commit 5688587b9031073d95c8af5e878cf6ce8f3c0962

Flashing the bootloader is risky.

If you like expensive bricks proceed without caution.

You will need a working Serial Console and a TFTP server.

From the Serial Console (UART) : Option 9