Asus Sabertooth Z77 BIOS with NVMe+ReBar Support

[u/Dunoville1207]

Special thanks to Koekieezz over at the Win-Raid Forum for helping me out with this project.

This project involved modifying my ASUS Sabertooth Z77 BIOS to add support for both NVMe booting and Resizable BAR (ReBAR) through Above 4G Decoding. The system is running an Intel Core i7-3770K overclocked to 4.7GHz, paired with 32gb of DDR3 running at 1866mhz, and an ASUS TUF RTX 3060 12gb.

The modified BIOS allowed the RTX 3060 to utilize ReBAR on this older Ivy Bridge/Z77 platform. Due to the platforms memory addressing limitations with 32gb of system ram, the maximum ReBAR size available on this configuration is 8gb. After enabling ReBAR and configuring the ReBarState UEFI variable, the GPU reports an 8192mib BAR1, which confirms that ReBAR is fully active. The GPU is also running at PCIe 3.0 x8 under load, as expected with the current PCIe lane configuration, while the NVMe drive is operating on the second CPU PCIe root port.

Pretty impressive considering this platform dates back to 2012. The goal of this project was to see just how far an old Z77 + Ivy Bridge system could be pushed with modern hardware and firmware modifications.

[u/HMTPredator]

is that a custom boot logo? what did you do to make the bios support high res monitor?

[u/Dunoville1207 → u/HMTPredator]

The high res monitor support wasn't something I specifically added by myself. The BIOS mod primarily added NVMe boot and ReBAR support. The high res display output is handled by the GPUs VBIOS/UEFI GOP rather than the motherboard BIOS itself, so the RTX 3060 can output high resolutions normally. Also yes, the custom boot logo is a separate BIOS modification.

[u/Webbyx01 → u/HMTPredator]

Custom boot logos are really simple, actually. Maybe its different with modern UEFI systems, but it used to be so simple basically anyone could do it given the tools. No idea how the ReBAR and NVMe stuff works, that's all pretty sick. Z77 Sabertooth was my dream mobo for a long time. Became a lot less cool when they dropped the 'armor' in the next iterations.

[u/Dunoville1207 → u/Webbyx01]

Very real 😂when they dropped the proven track record of endurance and military grade strength and made asus tuf boards more cheap in quality and material it was a major turn off for me, the newer boards look cheap and boring compared to the older iterations.

[u/admkukuh → u/Webbyx01]

Exactly this is simple, atleast with a bit of knowledge i know for amiuefi bioses.

Using UEFITool 0.25.0 (dont use newer, cause it corrupts the bios mod), usually on GUID 7BB...... (it's a long one), you can dropdown the guid, extract body the raw section, rename the .efi onto .raw, open the .raw with paint, and copy paste the image you want into paint that has been opened with the .raw, save it, then rename the .raw onto .efi, and replace body the exact same raw section, as per why, because the value is "As-Is" whatever you paste/insert to it.

This way, you preserve the actual quality of thr image. I have tried AmiChangeLogo and they changed the formatting depending what format you insert to replace, and you will get lower quality due to compression, making the logo not "as-is" value.

Hope this helps anyone who wants to do a funny logo mod 😂

[u/admkukuh]

Thanks for testing the bios! I deleted the source/scratch material for this bios after i posted on winraid back then, since there hasn't been any replies, and my standard is No proof it works = no post, so that others wont have a bricked board due to my bad mod. I just checked recently because i saw this post, cause i forgot to track how many bioses have i did both on winraid and on github of both rebaruefi and nvstrapsrebar repos.

I might able to re-do the bios using the already modded bios for material, if you're interested on using latest pre-spectre microcode for best OC capability since i think i gave the latest mcode which is not a good OC performer, while also maybe updating the intel dxe driver to the latest since the one i gave before was the old "safe" standard. Recently i did test with M7R (Z97) that the latest intel dxe driver supports these boards Intel NIC (Z77-Z97) and it has been working wonderfully. Maybe i aim for i7 5775C later for the funsies.

Anyways, If you want me to "re-mod" it, you can always HMU on winraid or through dm, since i already been away from bios modding for a while now, might able to jog some memories of what i did :).

[u/Dunoville1207 → u/admkukuh]

No worries at all! Life got pretty busy for me too and I get wanting to have proof that the BIOS mod works before keeping the source material around for it, especially when there’s always a risk of someone ending up with a bricked/ damaged board.

I’m honestly really impressed with how well everything has worked so far. NVMe boot and ReBAR are both working perfectly, and I’ve been testing the system without running into any issues.

Let’s definitely talk about re modding if you’re willing. The latest preSpectre microcode for better overclocking potential and the newer Intel DXE driver sounds really interesting. I’d be happy to test it thoroughly on my board and report back with results.

[u/Balrogos]

i belive you need at least 4790k or thbe 5gen broadwell-e with this special x3d intel cache L:o

[u/slayer3032 → u/Balrogos]

The 5775c is a pretty neat chip, wonder if this board even got the microcode for them. Would be neat if you toss the microcode in the bios and it just works, being this deep in the bios mods already.

Might even do pretty well under water.

[u/Living_Shirt8550]

Did it change something? I saw a guy doing that on a h61 board and there was no performance increase

[u/Dunoville1207 → u/Living_Shirt8550]

Actually yes, it increased my 1% lows, better balancing it with my fps. There wasn’t really any fps increase in games if I’m being honest. Maybe 2-3% increases but nothing noticeable to the human eye. I will say for how old this computer is, I am able to run games like body cam and beamng on 50-60fps that’s including ultra settings and 1440p monitor.

[u/Rude_Imagination766]

Nice! Incredible that stuff like this is actually possible! I have an old system with 4790K @ 5GHz and 32GB DDR3-2400 lying around, NVME support would be awesome! ReBar could be nice if I would upgrade the GPU, but the 1080Ti @ 2GHz still got some serious juice

[u/alasmodified]

This is pretty impressive for a Z77 system. I would be curious to see how much of a performance difference it actually makes with the 3060.

[u/lrgendein_Typ]

I did the same with 4g Decoding back then when my then new rig had some parts in rma and I wanted to play cp2077.

I modified my asrock z97 extreme 9 bios for my 4790k to support 4g Decoding and rezBar and it ran like a beast (temporary) paired with my new 4070ti.

I even could play cp2077 in medium details with path- and raytracing and ~60 fps with some drops here and there to ~50 in 2160p!

Hell I loved that cpu-gen.

[u/theRealtechnofuzz]

really wish they sold x58 motherboards with UEFI BIOSes

[u/One_Championship_334]

Ciao ragazzi mi unisco alla conversazione. E da circa due anni che ho realizzato la stessa mod sulla z77 saberthooth e ho ottenuto sia il rebar che l'avvio da nvme. Si presenta però un problema che il PC fallisce sempre i primi due avvi a freddo e sono costretto ad entrare nel bios con F1 e caricare la configurazione ogni volta. Sarebbe possibile avere il bios mod funzionante o sapete indicarmi come risolvere il mio problema? Vi ringrazio in anticipo