[coreboot] DediProg EM100Pro with Apollo Lake

[Urs Ritzmann]

Hi everyone

Are there any known quirks required to use the DediProg EM100-Pro flash emulator with Apollo Lake?

I'm trying to emulate a serial flash with the em100 for an Apollo Lake based SoC (Celeron J3355). It seems that Quad IO Reads (0xEB) do not properly work. I see too many bytes returned in the trace, somehow causing an offset. I used the ifdtool option --em100 to set the lowest possible bus frequency and disable Dual Output Fast Read. Is there a known bit in the firmware descriptor to disable Quad IO and Quad Output? Any available documentation about Intel's firmware descriptor?

I used the original BIOS/UEFI firmware which works fine when flashed to a real N25Q128A11. Emulation of the same flash and firmware doesn't.

Many thanks,
Urs