U-boot is an open source bootloader. This post is here because I had a problem with U-boot where I couldn't update it using ethernet.
It's not that difficult to use serial line for u-boot upgrading, as long as you have a "working" u-boot flashed in your board, you can always use loady or loadb to download binary image into your board's RAM.
For achieving this, we'll need:
- A target board with u-boot running;
- A new u-boot binary;
- Minicom;
- a serial cable.
Let's do it, step by step. By the way, I'm using an OMAP 1710 H3 board, so be aware memory offsets in your board may change.
- Attach a serial cable to your board;
- Open minicom by issuing:
- Start your board and stop u-boot's autoboot;
- run:
- Issue CTRL+s at U-boot and choose ymodem
- Wait until the image is loaded into memory
- After the image is loaded in RAM memory, it'll return you the amount of transfered bytes.
-
# protect off 00000000 0001ffff
-
# era 00000000 0001ffff
-
# cp.b 0x10000000 0x00000000 size_in_hex
-
# protect on 00000000 0001ffff
$ minicom
in a terminal;
# loady 10000000 115200
at u-boot's prompt;
And that's all. Restart your board and you'll have a new U-boot flashed.