Hi,
I wanted to exploit U-Boot's EFI support on the Espressobin board, to use off-the-shelf arm64 distribution installer images. This should work with current U-Boot, which has support for the Espressobin board (and for UEFI).
The firmware my board ships with seems to be built from older and non-upstream sources - and, in contrast to the Macchiatobin board - I cannot find either proper sources for all components (mv-ddr, ATF) nor *any* kind of instructions how to (re-)build and update the firmware.
So I was wondering if there are any instructions or documentation I missed on how to update at least U-Boot?
I see some hints that people are apparently chain-loading mainline U-Boot, is this the only way? I dumped the SPI flash and could identify the ATF FIP image on it, but I am a bit wary of bricking the board by just squashing a freshly built u-boot.bin into that - which I guess wouldn't work that easily anyway.
And to allow experimentation: Are the boot selection jumpers actually working? Setting them to SD card (111) doesn't seem to make a difference (it still booted off the SPI flash, apparently). Or does it fall back to SPI flash in case the SD image is not valid (I put the dumped image at sector 1)? I see that selecting "UART" (110) gives me that "E" prompt, apparently waiting for some data to be fed, but again can't tell what to do from here? I take it that mkimage/kwboot won't work as is, as it needs ATF? I found some mentioning of a Windows binary, but hope that's not the only way to use this mode?
I'd be very grateful for any insight into this!
Cheers, Andre.