Hello, I recently bought a NVMe drive, and had to mod my bios with NvmExpressEXS_4.ffs to add support. It always boots up fine the first time turning on after flashing, but within a few boots, the board gets stuck at finding boot device. I won’t be able to enter the bios or do anything, only power it off.
The workaround I have right now, is keep a flash drive in the bios flashback port with the file on it to reflash whenever it doesn’t boot (every 3-4 reboots usually). Once it does work, the board sits at a black screen with the grey underline cursor blinking in the top corner and center of the screen for 5 seconds, then it boots fine.
I am unable to upload the mod because its more than 6MB but I can take screenshots of anything. I’ve done this several times so I do not believe I messed up anything, especially because it works for the first few boots.
Thank you
@orz_nick - maybe bad mod? Upload your modified BIOS, and the stock same version too, and I can check it for you.
Put both in a zip or 7zip archive, if that’s still too large to attach, then upload to a free file host, here’s one I use often - http://tinyupload.com/
If BIOS mod is fine, maybe the NVME is damaged/dying etc, you never know, hopefully you can RMA it
Thank you for your reply, ill upload everything when I get out of school. The NVMe is a few months old with <1TB written so I hope it is ok, but we’ll see.
@orx_nick - mod BIOS looks good to me, I could only suspect either the NVME itself possibly, or the drivers used in OS, or the RST EFI/oroms in the BIOS possibly could cause some issues as well (Current versions 12.7.0.1936 for both)
Did you try moving your NVME around to another slot, maybe that could help?
Tried moving it to the bottom slot, worked a few times but resulted in the same issue I’ve had. If there anything else you think I should try or should I start the RMA process?
I’m just not sure how it’s the NVMe itself, Windows runs buttery smooth, never has corrupt files, no BSOD’s etc, just booting is an issue. Would the placement of the NVMe driver in the bios make a difference?
Well I think the oroms could be updated and maybe that could help, but I doubt they are causing this issue, unless there is some known conflict with the current version and your NVME device and you just aren’t aware of the issue/conflict.
Did you already test a few driver versions in windows? Specific: NVMe Drivers
Recommended AHCI/RAID and NVMe Drivers
What driver are you using, and what is the actual device model? Maybe @Fernando can suggest best drivers for you? (Current stock BIOS modules both =12.7.0.1936 - for your reference Fernando)
Also, I can make you a BIOS for testing with updated RST orom and EFI modules if you want to see if that helps. Did you try both ways of secure boot enabled/disabled + CSM enabled/disabled, to see if maybe only one of the BIOS RST modules causes this issue (orom Legacy one, or EFI)
No, you placed the NVME module in the correct location in the BIOS, that’s all done correctly so it’s not that. Are you using the latest BIOS Version, I didn’t check? If not, maybe update to latest version could help too.
* Edit - @orz_nick - Here, I used stock BIOS and made you test BIOS with updated RST legacy orom = v13.2.2.2224 + RST EFI module = v13.2.0.2134 + reinserted NVME
http://s000.tinyupload.com/index.php?fil…611716902686274
Use v13.2.x.xxxx drivers - Recommended AHCI/RAID and NVMe Drivers
+ You may need to also install NVME driver from here too, unsure? Fernando will have to advise you on that Recommended AHCI/RAID and NVMe Drivers
Flash via USB Flashback
@orz_nick :
I agree with @Lost_N_BIOS regarding the possibilty of an interference between the added NVMe module and any other natively present BIOS module. It is very much unlikely.
Since a negative impact of any other BIOS modification on your system can not be excluded, I suggest to concentrate your efforts on being able to boot and to reboot properly and permanently. Once the current problems have been solved, you can try to update any of the already existing BIOS modules.
Meanwhile I have done some tests while trying to add the NvmExpressDxe_4.ffs module to the original BIOS 2302 for your ASUS Sabertooth Z87 mainboard and got slightly different results by using different BIOS modding tools.
My question: Which BIOS tool did you use?
Attached is the BIOS, where I have just inserted the NvmExpressDxe_4.ffs module “as is” (like you did) into the original ASUS BIOS 2302 by using the AMI Aptio IV UEFI MMTool.
Since the hex code is not identical with the BIOS, which you had modified, it may be a good idea to flash the attached BIOS via USB Flashback and to report, whether your problem has been solved or not.
If you want any help from my side regarding the choice of the “best” Intel RAID driver and BIOS module combination, you should post your request within >this< thread and give me some additional information:
1. Have you set the on-board Intel SATA Controller to “RAID” at all? If yes, did you create an Intel RAID array? If yes, which sort of RAID array is it?
2. Which Disk Drive has been your system drive (containing the OS and the boot sector) before you inserted the NVMe SSD?
3. Which OS are you running?
Z87ST_modbyfernando.rar (4.8 MB)
@Lost_N_BIOS I have tried your updated bios mod, and it worked for 8 reboots then failed sadly. If nothing else works I can just flash that every few times. Thank you so much for putting time into making one for me, I appreciate it!
@Fernando I used UEFI Tool when modding so that must have been the difference. I flashed your bios and I’ve gone 20+ reboots without an issue, and it moves past the post screen faster too. I have to leave so I can’t test any longer but I will tonight to be sure. I’ll also post on the thread you referenced later so we can try and get that sorted out for good measure. Thank you so much for doing this for me!
Thanks for all the advice there @Fernando !! 
It also seems like MMTool works better for this particular BIOS, did you find the difference/reason why after checking doing the mod both ways? I used UEFITool 25.0
@orz_nick - thanks for report back, 8x boots is better than 3x boots before the issue, but still not how it should be. It sounds like Fernando’s BIOS is working properly so far, hopefully that resolves it for good and we can all try to remember MMTool instead of UEFITool for Asus Z87
I have this same motherboard and I tried to use this file. I’v used auto renamer put the file (Z87ST) on fat32 usb 2.0(16GB), placed USB on dedicated flashback slot, held down flachbackbutton, it started blinking after few seconds it turnd to solid light and stayed that way. When i restart, it post, old bios isnt corrupted but nothing happens? Am I missing something?
PS Im new here, stumbled across this forum when I got interested in putting nvme in my system, first of all i want to say thank you fernando(Dieter) for massive research on this topic!
Also If flashback doesn’t work can I extract bios from .cap to .bin and flash it with AsProgrammer(CH341A)?
@AOX :
Welcome to the Win-RAID Forum!
The BIOS file name should be Z87ST.CAP.
If the USB Flashback feature shouldn’t work nevertheless, try another smaller sized USB 2.0 flash drive.
Good luck!
Dieter (alias Fernando)
@AOX - Sounds like your USB stick might not be compatible (smaller = better, like 128MB-2GB) Sometimes you might need to try a handful of USB until you find one that works. Best thing to do is first test flashing stock.cap BIOS (renamed to Z87ST.CAP), once you find USB that will flash that, then mod BIOS named Z87ST.CAP will work
No, you cannot use stock BIOS like this with programmer, even if you extract the body from the capsule, you’ll loose your serial, DTS key, UUID, LAN MAC ID etc. If you want to use programmer, you first need to dump your BIOS with programmer, then do the NVME mod (or have someone do for you), then program that file back.
Thanks for response @Fernando @Lost_N_BIOS ! I’v added .cap so now its named Z87ST.CAP.CAP (last (.cap) as i have file name extension view turned on in windows), right? will try with alternative smaller sticks, I thought as well big size maybe an issue for motherboard to detect. Will update you with progress 
That was not a good idea. The BIOS should be named Z87ST.CAP.
Ohh, I must have misunderstood. The name is now "Z87ST.CAP" but my windows displays it as "Z87ST.CAP.CAP", bcs file extension is displayed. Initially when i made post it was named "Z87ST" , and windows bcs file extension is displayed showed Z87ST.CAP.
Which file name does the Windows Explorer show?
File name, including extension must be Z87ST.CAP (ONLY)
Here’s image: https://ibb.co/9353ky1
It’s named in same scheme as yours uploaded, I misunderstood first time…tried with another 4gb stick, no luck…but it flashes for longer time like 1 min and then goes solid, will find another smaller sized tomorrow.
Success!
- Looks like smaller sized USB stick was key (2GB).
- Later on proceeded to clean install, before installing disabled fast boot, secure boot and CSM. (Turned fast boot on later again after installation)
Everything works great got some amazing nvme (970 evo 500gb) speeds. Secondary disk for apps is 960GB ssd. And for data I got 1TB hdd (later on maybe Ill add raid card and another 1TB which i have laying around).
Now I’ll research forum too see best drivers for my chipset.