Ah, so you change the straps from the command line with nvflash.
I actually edit the straps while I'm editing the ROM. I find it easier because all I have to do afterwards is flash the ROM, although I do make sure that nvflash verifies my ROM first.
I may be wrong but IIRC NiBiTor doesn't update the strap checksum, only the full checksum.
I got to that point without heating up my soldering iron.
For me, Windows Quadro driver would not install if I do not change hard-straps. Matter a fact in some cases I could not even get to Windows GUI to install the driver.
Sounds strange, I've never seen an issue like that on any of the cards I modified, it always "just works".
Then again, modifying a GTX580 is a complete waste of time anyway. GTX480 is just as fast (in some cases faster due to dual DMA channels when modded to Quadro/Tesla), and is trivial to modify into a Q6000. I only modified my 580 because I already had it and I was seeing odd driver clashing when using a GeForce and a Quadro in the same system under Windows. One driver would end up driving both cards, usually the later one (the GeForce one has a higher version number).
Hmm... I wonder if this could be stripped out to reduce the BIOS to the old, EFI-less state that is more open to modifying. It'd also make it a lot more similar to the previous BIOSes in terms of understanding what the various bits do.
That should be doable, but you have to make sure that you include all ROM parts (minus the EFI). In Fermi cards, the ROM had two parts (one was the vbios and the other another device, I believe HDMI audio).
Indeed, but you get the same thing on Kepler, they have a HDMI audio device, too.
I don't own any EFI motherboards, but I would have thought the whole EFI wrapping should be strippable out from the VBIOS. Once you skip past the 0x400 bytes of header, the rest of the BIOS is similar in terms of offsets of known areas to the Fermi BIOSes.
IIRC, according to the PCI firmware spec the wrapping stuff ends up being ignored on older computers with BIOS, until the 55 AA signature is detected. On the new UEFI, they will probable read the wrapper and then read the rest (55 AA, on).
Handy, so you could effectively s/.*55AA// and strip out the EFI capability and defeat crypto. Nice. Presumably the trailing garbage would just get ignored then.
The only question is whether there is an extra ID bit in Kepler soft straps. These are not yet fully documented. It could be one of the unknown bits (but it's not the unknowns next to ID bit 4, I tried those). The reason I say that is because until Kepler, all cards were modifiable using only soft-straps into any other card sporting the same GPU and memory type. And I only mention memory type because the GDDR3 GTS450 differed in more than just the last 5 bits of device ID, I had not seen such a case before.
What I'll probably do on my GTX680 is mod the resistor slot controlling the 3rd nibble by adding a dip switch, so I can toggle that bit between 1 and 0. From there on, I can modify the GTX680 into any card sporting the GK104 chip using the switch the 5 soft-strapped bits.