ASUS TUF GAMING Z790-PLUS WIFI - BIOS Help

[grimacelord]

Hello,

I have spent the last hour on this and I guess this is just over my head, so here I am.

I have an ASUS TUF GAMING Z790-PLUS WIFI motherboard here that needs to have the BIOS updated in order to accept the latest CPUs.

The BIOS chips seem to come as a set of two: GD25B64ESIG and GD25B128ESIG. My guess is one of them is a fail-safe for the main BIOS? I really don't know. Or one of them is ME and other is BIOS? I don't know.

Anyway, I took dumps of both chips and then downloaded the latest update for this motherboard from ASUS's website and this is basically where I am stuck. The downloaded .CAP file from ASUS's website is 24,580KB. The dump I took from GD25B64ESIG is 8,192KB and the dump from GD25B128ESIG is 16,384KB. If you were to add the file sizes of my two dumps, it would add up to roughly the size of the downloaded .CAP file from the ASUS website.

The problem I am having is I have absolutely no idea how I can go about flashing this new BIOS to the chip when they are separated between two chips like this. It seems to me like the original dump will need to be edited in a HEX editor to have the .CAP update "merged in" or something and I am still not skilled enough in this area to do this. I have read over the guides here a million times and watched countless YouTube videos and I have still just been unable to figure out how to successfully edit a BIOS file and have it actually allow the computer to boot. I've tried it before on other systems and failed every time haha.

I think I understand what needs to be done here, but I have absolutely no idea how to go about doing it, so I am here asking for help. Attached is the original dumps from both the 64MB and 128MB chips as well as a copy of the latest available BIOS update from ASUS's website. If someone could please take a look at this I would greatly appreciate it. Thank you.

Also, as a follow-up question. Assuming someone here is able to help me and edit the original BIOS dump to "merge in" the updated BIOS region or whatever needs to be done, I am assuming I am going to end up with a single file. I would flash that single file to the 128MB chip, I assume, but what does that do to the 64MB chip? Does the updated BIOS from the 128MB somehow automatically update the 64MB chip or will I have two separate files to flash individually to their respective chips? I don't understand how that part works. Thank you so much!

Also, in case I didn't make it obvious enough:

TUF-GAMING-Z790-PLUS-WIFI-ASUS-1820.zip = Downloaded ASUS Update file for this motherboard
GD25B64E@SOIC8.zip = Original dump for 64MB chip
GD25B128E@SOIC8.zip = Original dump for 128MB chip

[m1ch43lzm]

The "easy" way: Borrow a 12th/13th gen CPU, update BIOS from USB drive, install 14th gen CPU, done

The "hard" way: Open the .cap with UEFITool (no need if you follow the steps below), extract the Intel Image (should be 25,165,824 bytes), and manually split with a hex editor
The first 0x800000 go to the 8MB chip, the remaining 0x1000000 go to the 16MB chip

i tried joining the 2 files from your dumps: first the 8MB+16MB, and UEFITool showed an Intel image, with a Descriptor, ME, and BIOS regions, but it's corrupt
If using a clip, try changing the SPI clock frequency in your programmer to lower frequency to try to get a good read, then read the chips 3 times each and compare the dumps with a hex editor; if exactly the same, it's very likely you got a good read
Example: I have the T48, look for a setting similar to this, and lower the value (I set it to 8MHz when using a clip):


How your dump looks, vs how should it be:

______________________
Check here for reference:
https://winraid.level1techs.com/t/pr...fi-d4/108012/2

In short:
Download FD44Editor https://github.com/LongSoft/FD44Edit...ases/tag/0.9.2
Join your BIOS dumps with hex editor, in a new file, first the 8MB, then the 16MB, in that order, the contents of the 16MB file should start at 0x800000, the file should end exactly at 0x17FFFFF (length: 0x1800000), or exactly 25,165,824 bytes
Open your "full" BIOS dump with FD44Editor, use the "Open from BIOS image file" button, and note your S/N, MAC address, UUID, etc.,
Press "Save to BIOS image file", select the .cap downloaded from ASUS website, overwrite it; the .cap header will be removed and you'll be left with a .bin exactly 25,165,824 bytes, or 24,576KB

Now, split the BIOS image .bin with hex editor (I use HxD as an example)
Go to position 0x800000, Edit, set length to 1000000 hex
Ctrl-X, a warning about changing file size will appear, press OK
File - Save as a new file (example: 8MB.bin)
Press the "New file" icon, and paste (Ctrl-V), again the same warning, press OK
Save the new file (example: 16MB.bin)

[grimacelord]

Thank you for the help. I also use the T48 and I indeed used a clip on both dumps. I'll try again with a lower frequency as you suggested and see if the dumps are the same after 3 reads.

As far as the process goes, thank you for explaining that so clearly. I think I might be able to follow that. I'm going to give it a try and if I fail miserably as I have in the past at this sort of thing, I'll post back with fresh dumps and maybe you could give it a try? Haha.

I really appreciate your help. I'll be giving this a try in about an hour...

[grimacelord]

Well, looks like I botched it again somehow. I felt like everything was going smoothly and I was getting the exact file sizes that you said I should, but I think I must've made an error when splitting my "full bios" file I created as per your instructions. After flashing my "split image" to each chip and attempting to boot, the computer doesn't POST.

I am attaching my new dumps that I took after I set the frequency to 8MHz (verified with 3 dumps) and I am also attaching my "full bios image" I created according to your instructions as well as my "16mb.bin" and "8mb.bin" images I made after I split them so you can see what I did and perhaps show me where I made a mistake because I am sure that I did somehow. This BIOS editing stuff always seems so complicated to me. I thought I had it for sure this time, but I guess I screwed it up again.

Attached are my files.

"8mb.zip" = My attempt at splitting the "full_bios" image to create the 8mb image
"16mb.zip" = My attempt at splitting the "full_bios" image to create the 16mb image.
"GD25B64E@SOIC8@8mhz.zip/GD25B128E@SOIC8@8mhz.zip" = The newly created dumps I made with reduced frequency to 8mhz.
"full_bios.zip" = The "full bios" image I created by joining the two in HEX editor. The file size matched what you said it should, so I felt like I did everything right up to this point, but you may want to check this too. I don't know what I am doing. Ha.

Thank you so much for your help.

[grimacelord]

The "hard" way: Open the .cap with UEFITool (no need if you follow the steps below), extract the Intel Image (should be 25,165,824 bytes), and manually split with a hex editor
The first 0x800000 go to the 8MB chip, the remaining 0x1000000 go to the 16MB chip

I went back and tried this method and the resulting 8MB image I came up with was identical in hex to the first 8MB image I created, but the second 16MB image I made using the method above was different than the 16MB image I created the first time. I went back and flashed that 16MB image, hoping that I found my error, and still - no POST. Just figured I'd let you know everything that I have done. I'm still no closer to figuring this out myself, so I hope you are able and willing to help me. Thank you again.

[m1ch43lzm]

I'll check later your BIOS dumps, as I'm not on my PC right now
Test with the basics, just CPU, 1 stick of RAM, GPU if you're using a CPU without integrated graphics (CPU model ends in F)

[m1ch43lzm]

Your original BIOS is version 1402, it should work with 14th gen Intel CPUs out of the box

TUF GAMING Z790-PLUS WIFI BIOS 1402
Versión 1402
11.25 MB
2023/09/19

"1. Update Microcode for Intel® Core™ 14th gen processors
2. Update ME to version 16.1.30.2264v2 for Intel® Core™ 14th gen processors
3. Improve system stability
Updating this BIOS will simultaneously update the corresponding Intel ME to version16.1.30.2264v2. Please note after you update this BIOS, the ME version remains the updated one even if you roll back to an older BIOS later."

The issue may be somewhere else

The way you split the files is correct, just small differences in how the serial etc. are stored (using FD44Editor, vs doing it by hand copying from the original dump), nothing that affects POST
Even without serial, MAC address, UUID the board should POST

S/N, MAC, UUID are stored in those offsets, I copied manually to the new BIOS (those offsets are from the full image)
864000-86415F
A90090-A900CF
Attached the split files for BIOS 1820, now with your S/N, MAC address, UUID

As i said before, test only motherboard, CPU + heatsink, 1 stick of RAM in slot DIMM_A2, GPU if using a "F" CPU(without integrated graphics), nothing else connected to the board except keyboard/mouse/monitor (connected to GPU, or the onboard HDMI port if no GPU installed); it will take some time, give it 5 minutes for the 1st boot

[grimacelord]

Your original BIOS is version 1402, it should work with 14th gen Intel CPUs out of the box


The issue may be somewhere else

The way you split the files is correct, just small differences in how the serial etc. are stored (using FD44Editor, vs doing it by hand copying from the original dump), nothing that affects POST
Even without serial, MAC address, UUID the board should POST

S/N, MAC, UUID are stored in those offsets, I copied manually to the new BIOS (those offsets are from the full image)
864000-86415F
A90090-A900CF
Attached the split files for BIOS 1820, now with your S/N, MAC address, UUID

As i said before, test only motherboard, CPU + heatsink, 1 stick of RAM in slot DIMM_A2, GPU if using a "F" CPU(without integrated graphics), nothing else connected to the board except keyboard/mouse/monitor (connected to GPU, or the onboard HDMI port if no GPU installed); it will take some time, give it 5 minutes for the 1st boot

Thank you again for your help. I won't be able to get back to this until Monday, but I'll try this first thing Monday morning and let you know how it goes. Have a great weekend!

[grimacelord]

Hello again,

I finally was able to give this another try, but unfortunately, I still have no POST.

I first flashed your files to each respective BIOS chip and then disconnected everything except for the essentials. Motherboard, CPU, a single stick of RAM in slot A2, and of course the power supply. I then cleared CMOS using the jumper on the motherboard, connected power, and powered on the computer and allowed it to try and POST for about 10 minutes the first time. Then, I shut down the computer, tried adding a GPU card and switched the HDMI cable to that, CMOS clear again, and try to POST again. 10 minutes later, still no POST. Next, I tried a completely different stick of RAM altogether (still compatible, just different manufacturer) and again, no POST.

Not really sure what to try next...

[m1ch43lzm]

At this point I think you have defective motherboard or CPU
Inspect the CPU socket pins with a magnifier or microscope, check if you have bent or damaged pins
If CPU socket is good, only way to know is swapping parts, testing the CPU/RAM on another motherboard

Have you checked the debug LEDs at the top, near the RAM slots? Where does it get stuck

If all else fails, and there's no visible damage on the CPU socket, RMA the motherboard (reinstall the socket cover)