Z87M OC Formula - Debug Code 28 / won't boot

Thaddaeus wrote: Hi all! I am a happy owner of the Z87M OC Formula with a delided I7-4770k on it. I had a rock stable clock to 4.5 @ 1.225Vcore for the past 2 years until yesterday when I decided to change CPU coolers: yesterday I tossed out my Corsair H110 for the Noctua NH-D15S. I made the switch and wanted to start the system but ended up with no signal on the Screen and no power to Mouse or Keyboard. The Dr Debug code is stuck at 28. It stays at 28 for one minute after which it will reboot and end up stuck at 28 again. Only hard-off will switch the system off. The thing is that I thought that I  may have damaged the RAM or CPU, but the system boots into UEFI and Windows without a problem if I switch to BIOS 2. Here is what I changed besides the rockstable system and the currently code 28 stuck one: Exchanged CPU cooler (this shouldn't cause Code 28) Exchanged GPU from PCI-E Slot 1 to 2. ( I changed the gpu back to Slot 1 after I got code 28 the first time, but this doesn't make a difference anymore). Changed Case Fan header from PWR fan header to CHA Header 1. Here is what I tried: Only one RAM module installed, different RAM slots, no RAM (which obviously ends in code 55). CPU taken out of socket, re-installed. GPU back to Slot 1. Different memory installed. What I don't want to try (just yet) CMOS clear: I know, this would be the obvious next step. Yet, I have a lot of detailed changed in my UEFI re. CPU OC and RAM timings and I of course forgot to write them down somewhere... What is causing this Problem ? As noted, System boots fine in BIOS 2 and no hardware has really been exchanged. Is there a way to read -out the settings from BIOS 1 or maybe make it go to default settings without wiping the saved profile ? I hope you guys can help!

I should have good news for you, but some discussion first.

As you know, you seem to have two contradictory things going on here.

First is the Dr Debug code of 28, a memory problem, which given the CPU delid, hints at bent pins in the CPU socket. I'm just saying that changing the CPU cooler with a delided CPU is a situation where it would be more likely for bent CPU pins to occur.

But then we have the fact (right) that the PC starts into the UEFI UI, and loads Windows when using the backup UEFI in the CMOS B chip. That tells us that there should NOT be any bent CPU pins.

A quick diagnosis of the 28 POST code is the change in the location of the video card caused a need to clear the UEFI/BIOS. Any time a major hardware change occurs, and moving a video card to a different slot is unfortunately a major hardware change from the perspective of the UEFI/BIOS, we must clear the UEFI/BIOS before starting the PC again.

We have seen many times a POST/Dr Debug code related to memory when a change to the video source of some kind was done. This must be related to the fact that a video card uses system memory.

The good news is, and I'm 100% certain of this since I've done this many, many times:

IF you have your OC settings (or any non-default UEFI settings) saved in a UEFI profile (saved in a UEFI profile being the most important thing that was done), then if you simply clear the UEFI/BIOS via the board's jumper of clear CMOS button, you will NOT loose any saved profiles.

The only situation where UEFI profiles are deleted/removed is if you perform a UEFI/BIOS update. This of course includes restoring the A UEFI/BIOS from the B backup UEFI/BIOS chip. I don't know if you were considering doing that, but I include this to be complete.

So what I suggest you do is change the UEFI/BIOS selection switch back to the A position. DO NOT perform a Secure Backup UEFI, since that will remove your saved profiles. That is a tool in the UEFI UI, Secure Backup UEFI.

Of course the above is done with power removed from the PC. Next clear the A UEFI/BIOS with the board's jumper or button on the IO panel.

I save UEFI profiles all the time, and normally run out of the number I'm allowed to save. I KNOW for a fact that clearing the UEFI/BIOS does NOT remove UEFI/BIOS profiles.

ONLY performing a UEFI/BIOS update will remove UEFI profiles, or over-writing them ourselves by changing settings and saving them in an existing profile "location", 1, 2, 3, etc.

Another way to save UEFI profiles is with the save profile option in the UEFI, but by saving them to disk. Some ASRock boards provide this option, I'm not 100% sure about yours. Your board's UEFI OC Profile screen will have an entry about saving a profile to disk, if you have that option available.

I've had odd results when trying this option. When starting the save profile to disk option on a different ASRock board than yours, it seemed to only let me save the profiles to a Windows system/reserved partition on the OS drive, rather than the user partition. I could not seem to choose a different partition besides the one (as I recall) I was allowed to use.

There of course is a load profile from disk option on the same screen, which gave me more than one option for the partition to load from. Which leads me to the next option.

Yet another way to save a UEFI profile is with your board's Formula Drive utility provided by ASRock. Current/new ASRock boards seem to no longer have this option, I believe your board will. In the Formula Drive program is an option to save UEFI profiles to disk.

A question about this is whether or not a UEFI update will remove the profiles saved to disk. That is one thing I am not sure about.

Or am I missing your point completely here?

So, i tried to do a cmos clear, but sadly it doesnt work. Tried with the button on the i/o panel as well as the clr cmos jumper. Still, code 28 and nothing else upon boot.