Z390 Phantom Gaming 4S/ac BIOS mod for Resizable BAR

I wonder if there is any diference on the original 4S non AC compared to 4S only bios, but also this experiment means that you could keep the board bios up to date!

i remember vaguely but on 2021, on reddit a redditor have a complaint about this but not rebar, more to latest bios. i have a tought about “maybe flash the bios region of original counterpart would work, overriding 4S bios with 4S/ac board since they’re identical” and the rest is just a tought/theory to me :stuck_out_tongue:

Idk what gpu you are on but if your gpu is 8GB then it should be 8GB, working as intended :smiley:

*since your board does have an AC Wifi module did it still work?

Everything is identical. Between both boards, the only difference appears to be that one was OEM so it came in a “pre-built” maybe like “bare-bone system” I am not sure how they sold it, but the one I bought, came with a m.2 ac wifi card, but I replaced it with a better one that that uses the AX protocol of wifi6, then I just use “intel driver update assistant” and it works fine.
the layout of everything is absolutely identical. I dont know why ASrock would lock the bios like that. No reason at all…

I have the latest bios now, and this is now an unsupported platform so, no new bios will be coming out for it anyway. but this clever access memory is all I cared about.

Yes I have the AMD 5700XT which comes with 8GB vram, I did not know that the re-BAR was meant to simply match the VRAM amount, makes sense now that I think about it.

Here is the OEM board

Here is the Retail board


Yeah i forgot to tell about you that on asrock it is sometimes called C.A.M instead of regular rebar, as far as i remember on b450 and b550 build that i built for my friend it is still called rebar… maybe got bad memory about it XD

And yeah, rebar always meant to match your vram, since thats how much the cpu could access the vram directly.

Hi!! Can someone upload the 1.40 version modified? Thank u :smiley:

no need modified bios for it i guess, you could just flash (or crossflash if your mobo is 4S/ac ver) version 1.40C version. disable CSM and find resizable bar option, enable it, and find Clever Access Memory option and enable it.

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Yes, Koekieezz is right, he gave me the idea of using the FPT64.exe program, but I am the one that actually has the motherboard in question, and performed the modification, and I am want to verify what he said and say that there is no BIOS modding involved when you flash the 1.40C into the 4S/AC version, hence why we refer to this process as “crossflashing” throughout the thread.

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