hi guys look that Asus rog g75 and g750 are both deadly vga upgrade because of custom design that Asus did for there new laptop, the big problem they add a security to the bios and I want to upgrade the gtx670mx 3gb on rog g75vx to gtx880m 8gb(rog g750 vga) pls any help for modding the bios of g75vx i think he need just replace gop id ,thnx

What? Please explain in more detail, in single for each thought and each system, thanks

BIOS security can often be gone around, depending on what hardware you have on hand, or what methods you utilize to unlock locks.

Do you have hardware programmer CH341A or similar, and SOIC8 test clip cable?
If not, I suggest you stop now until you have those things in your hand, otherwise you may be out of a running system for 3-5 weeks+ unless you have other system to use while this system sits bricked waiting on your flash programmer to arrive.

well thank's for your reply maybe I don't explain my problem very clear ,about the programmer yes I have tow sof8 and ezp2010 and I use raspberry pi too. the problem is when I put the gtx880m 8gb on my laptop g75vx there's no signal no power but when I put the gtx670mx which is the original graphic card the laptop work fine !!!! I read that the bios need some modifications (replacing id gop gtx670mx with id gtx880m),

Yes, I wasn't quite sure what you were asking to be done. It's great you have programmer!

Thanks for explaining differently. So you need gtx880m vBIOS into your main BIOS, correct? Do you have the vBIOS from within some other laptop, or similar laptop (Same brand would be great, but same model with updated GFX card already would be even better)
If you have that BIOS, that contains the gtx880m vBIOS please attach it. If you do not have this vBIOS or a BIOS that contains it, you need to find, then bring a copy here.

thank you again, for more details there is no rog g74 series with gtx880m max gpu is gtx680m because gtx880m come only with rog g750 series and yes I have both bios of them that I had attached on my first post (G75VX.rar & Asus G750JZ Rev. 2.0 T4030H Ver.207.zip)

OK, thanks. So gtx880m vBIOS is inside g750 BIOS in post one? I'll check this out tonight, and have edited BIOS for you soon.
I'm so "Safety" orientated, I almost asked again "DO you have flash programmer" Because, it may not work of course, but we can try!
It may not work at all, due to different settings in each specifying what traces go to what outputs etc, this can't be edited with any tools the public has for Nvidia BIOS that I've seen.
But, and hopefully, all that is only controlled by the embedded onboard vBIOS/GOP modules. If not, I also see two GUID's with Nvidia ACPI raw files, we can swap those out if first mod does not work

*Edit - the G750 does not have vBIOS as part of the BIOS, like your G75 has 4 x Nvidia roms in it at two different locations.
I sure this is due to your video card is part of the motherboard itself, and the G750 has add-in PCIE card not part of the motherboard itself so it's vBIOS would be on the card (Exported by GPU-z, which you can't do since it's not a card for yours)
So this is not possible to even try

ok so I will dump the eeprom file from gtx880m and send it to you ;)

That will not help, please read my last paragraph again. This is not a possibility due to your G75 had no actual graphics card, the GFX is part of the motherboard itself, while the G750 has actual video card separately from the motherboard
vBIOS contained in flash on a GFX Card is not same thing as vBIOS put into BIOS itself. Summary, this is not possible to do, nearly 99.9% sure.

If you have flash programmer you can try it, but I do not advise without programmer in hand and valid verified backup of the original BIOS confirmed and checked as OK and valid.