My Lenovo LOQ 15APH8 stopped booting Windows after the motherboard was flashed with the BIOS for the wrong board. Windows now crashes with ACPI_BIOS_ERROR 0xA5 and these parameters: 0x0000000000001000, 0x0000000000000000, 0x0000000000000000, and 0x0000000001000000.
Linux still boots, but it reports several ACPI errors, including AE_NOT_FOUND for GP18.SATA and GPP0.PEGP.GPS.NVD1, plus AE_ALREADY_EXISTS errors involving GPP6.WLAN, GPP6, GPP6.WLAN._S0W, GPP6._PRW, and I2CA.TPDD. The laptop originally received an incorrect BIOS flash, after which the correct BIOS was flashed externally. I also tried flashing it again using the manufacturer's crisis-recovery mode, but Windows still fails. What should I try next?
2 Answers
How was the older or incorrect firmware replaced? The manufacturer’s download page may only provide a Windows-based updater, while a board that has already been flashed incorrectly may require an external programmer or a dedicated crisis-recovery procedure.
Booting Linux while Windows fails immediately with ACPI errors strongly suggests that the firmware’s ACPI tables or stored NVRAM settings are inconsistent after the incorrect flash. Reflashing the main BIOS image does not always reset every stored table or configuration value.
First enter the firmware setup and choose Load Factory Defaults or Optimized Defaults, then save and reboot. If that changes nothing, perform a complete CMOS or NVRAM reset: disconnect power, disconnect the internal battery if practical, and hold the power button for about 30 seconds before reconnecting everything.
If Windows still produces the same 0xA5 error, the laptop may need the exact BIOS and embedded-controller firmware combination for that motherboard revision. Reflashing only the BIOS may leave the EC and ACPI data out of sync, so using the manufacturer’s full recovery package or having an authorized repair center reprogram the chip may be necessary.
The current BIOS version is the latest one, but the original problem started when firmware for the wrong motherboard was installed. The correct image was then flashed externally, and I also tried the manufacturer’s crisis-recovery method.