A good tutorial for compiling uboot.ext?

[Bozza]

Hello everybody is there a good tutorial to compile u-boot.ext?

Or are there perhaps any quality sources that already have u-boot.ext files?

 

Thank you

[jock]

9 hours ago, Bozza said:

Hello everybody is there a good tutorial to compile u-boot.ext?

Or are there perhaps any quality sources that already have u-boot.ext files?

 

Thank you

What is u-boot.ext ?!?

[Bozza]

It is the bootloader. 

[SteeMan]

More specifically, balbes uses a second stage bootloader in a file named u-boot.ext for the amlogic platform in his builds. 

[hexdump]

i think this was due to amlogic messing up the video mode with current mainline kernels in later versions of their legacy u-boot - the solution was to chainload a u-boot which sets the video mode properly (no more false colors) from the legacy u-boot on the box ...

[hanguofu]

Hi , hexdump : Do you know the related code about setting video mode  ? I would like to modify the legacy u-boot to make it right

[hexdump]

i do not know any details, i just know that is why the u-boot.ext was there ... maybe just give a mainline c4 u-boot a try and chainload that? i would not recommend to touch the legacy u-boot on the box as long as you do not know 100% what you are doing (maybe you do know 100%) as its very easy to brick a box this way due to wrong memory timings

 

best wishes - hexdump

[Devmfc]

Maybe these helps as a start:

 

https://gitlab.com/baylibre/amlogic/atv/u-boot/-/wikis/home
https://u-boot.readthedocs.io/en/latest/board/amlogic/sei610.html

 

But it looks like the u-boot.ext Balbes uses is one without de binaries from Amlogic, since he is chaining his bootloader after the boards own u-boot, so memory initialization and soc initialization is already done.

Edited October 20, 2020 by Devmfc