Is this thing on? Using OpenBMC and ACPI power states for reliable server boot

This post details the customization and extension of OpenBMC firmware to improve server boot reliability and diagnostics. It addresses issues where servers would not boot despite the BMC indicating power on, and where memory modules were randomly missed. The solution involves better management of BMC and UEFI interactions during the boot process, specifically by leveraging ACPI power states (S5_G2, S0_G0) for more accurate power status reporting and by analyzing i2c bus contention between the BMC and UEFI when accessing memory module SPD data. This allows for more reliable server boot-up and better diagnostics.