RayeR wrote on 2024-04-07, 13:02:
AFAK modern boards cannot run without ME and if it was fully removed or corrupted this cause system shutdown. This is why someone created MEdisabler that remove/disable almost ME features but leave some criticals.that prevent the shutdown. But in normal case the BIOS modding tools.shouldn't touch the ME region, it's a different section of flashrom...
I eventually succeeded in modding the BIOS to enable that more-Advanced menu, but that's the only thing I could achieve without breaking it. The hidden menu has some interesting options, but nothing really LPC or DMA-related. I'm considering hooking a logic analyzer through the breadboard to find out what was really going on, regarding the LDRQ1# issue...
I guess it's just Aptio BIOSes being too complex and delicate. Actually changing existing modules, including uCodes, has a very good chance to cause the BIOS not to boot (brick). Fortunately my board has two BIOS chips that I can choose with a switch should the mod turned out not working...
On the other hand... I'm not sure how to "properly" modify the BIOS PCI IRQ routing table to avoid sensitive IRQs like 5/7 without side effects. The thing is, from AMIBCP, what IRQ a PCI slot/device can use is defined by a "bitmap", which I think each bit in it corresponds to an IRQ, and the IRQs whose bits are set in the bitmap can be picked up by the specified PIRQ register.
As such, while the onboard audio claimed IRQ7 through its own separate IRQ line and PIRQ register (not shared by anything else), I probably need to make a lot of (risky) changes in the routing table to make sure nothing else would end up in IRQ7, as I'm seeling a lot of bitmap entries in the PCI IRQ routing table permitting them to use IRQ7 (bit 7 set) if available.