Problems on warm boot with Maximux XI Code

[guiambros]

Configuration:
- Maximus XI Code, BIOS 1302 (9/02/19)
- CPU i9-9900k
- GPU EVGA RTX 2080
- 4x16GB Micron Balistix
- Power supply EVGA 1000 G3
- Monitor connected via DisplayPort (but also tried USB-C)

Problem: system boots normally after a power up. But when doing a soft reboot, the system gets stuck in post code A2 (or sometimes 78), and then it freezes. This happens 100% of the time. Blank screen; BIOS doesn't show up. LED lights: boot green; VGA, CPU and DRAM off. The only solution power down or reset. Power down works every time. Reset not always


What I tried:
- tested with two identical RTX 2080 GPUs
- replaced all power cables
- tried with memory configuration and modules (1x16, 2x16, 4x16GB)
- stripped all SSD and NVMe disks
- booting from a clean bootable USB stick (Ubuntu 14.04,
but also tried other versions)

In the BIOS:
- factory reset
- Fast boot - enabled, disabled
- AMI Native NVMe Driver Support - enabled, disabled
- CSM - enabled, disabled

I also tried booting with my original Ubuntu 18.10 from NVMe, but same thing. It works on cold boot, but not on warm reboot.

Weirdly enough, I had similar problems with another system also using a Maximus XI Code motherboard that had problems detecting the GPU. While I got that motherboard replaced, I remember seeing similar patterns - boot frequently stuck in A2 and 78 (but at the time I had a bigger issue with the GPU, so I wasn't too concerned with instability during reboots).

The only pieces I haven't tried replacing (yet) are the keyboard/mouse, and the CPU. But I doubt they would be the culprit, given everything else is stable.

I read the other posts with people having issues with BIOS 1302 and high memory voltage on the default settings, but mine has 1.2V on Auto after factory reset, which seems appropriate. I may try BIOS 1105, just to rule it out.

Any other ideas? Maybe something on Power Management or ACPI can be causing it?

[MrAgapiGC]

nop. that is the first time that I read that.

both codexi??.... sound like a cpu issue or power related. making changes on the bios, is not the correct way. cpu and board has to pass the lights and code and boot into bios and later windows. That is what has to do. Anything else are problems with cpu

i have work many codesxi and that issue, I has never see it before. and 2.... sound like cpu to me or psu or memory (less unlike it)

[Falkentyne]

guiambros wrote:
Configuration:
- Maximus XI Code, BIOS 1302 (9/02/19)
- CPU i9-9900k
- GPU EVGA RTX 2080
- 4x16GB Micron Balistix
- Power supply EVGA 1000 G3
- Monitor connected via DisplayPort (but also tried USB-C)

Problem: system boots normally after a power up. But when doing a soft reboot, the system gets stuck in post code A2 (or sometimes 78), and then it freezes. This happens 100% of the time. Blank screen; BIOS doesn't show up. LED lights: boot green; VGA, CPU and DRAM off. The only solution power down or reset. Power down works every time. Reset not always


What I tried:
- tested with two identical RTX 2080 GPUs
- replaced all power cables
- tried with memory configuration and modules (1x16, 2x16, 4x16GB)
- stripped all SSD and NVMe disks
- booting from a clean bootable USB stick (Ubuntu 14.04,
but also tried other versions)

In the BIOS:
- factory reset
- Fast boot - enabled, disabled
- AMI Native NVMe Driver Support - enabled, disabled
- CSM - enabled, disabled

I also tried booting with my original Ubuntu 18.10 from NVMe, but same thing. It works on cold boot, but not on warm reboot.

Weirdly enough, I had similar problems with another system also using a Maximus XI Code motherboard that had problems detecting the GPU. While I got that motherboard replaced, I remember seeing similar patterns - boot frequently stuck in A2 and 78 (but at the time I had a bigger issue with the GPU, so I wasn't too concerned with instability during reboots).

The only pieces I haven't tried replacing (yet) are the keyboard/mouse, and the CPU. But I doubt they would be the culprit, given everything else is stable.

I read the other posts with people having issues with BIOS 1302 and high memory voltage on the default settings, but mine has 1.2V on Auto after factory reset, which seems appropriate. I may try BIOS 1105, just to rule it out.

Any other ideas? Maybe something on Power Management or ACPI can be causing it?

Did you disable fast boot in windows power options?

[guiambros]

I tried with both fast boot enabled and disabled; same thing. Also CSM; no difference.

And yes, both motherboards are M-XI Code; identical. One is going back to Asus for RMA, but for an unrelated problem (GPU not detected). The second one is stable after the initial boot, but gets stuck in 78/A2 100% of the time after warm boot, and about 10-20% during cold boot.

Interestingly, when it gets stuck in 78, the mobo status LED indicates VGA solid white, all others off. But I've tested with two identical GPUs, so it can't be both having the same problem.

Everything is pointing to the processor, or some compatibility issue with the BIOS. Has anyone used Intel's RMA process?

[guiambros]

Well, this is embarrassing. After RMA'ing almost everything, I discovered the root cause for the problem: CSM. Seems some incompatibility between the video card and UEFI boot, particularly when booting on Linux.

This article gave me the first indication that the problem could have been CSM-related, but upon further reading I found more evidence of related issues.

The solution was simpler than anticipated: just enable CSM / Legacy boot mode. I am fully aware of the consequences of CSM / legacy boot mode, but in my case it solved all problems dual booting Linux, Windows 10, external USB sticks, and ensuring consistent BIOS display messages on every boot.