BIOS Problems on Pascal GPUs

Symptoms of having a problem with the BIOS.

 * All voltages (5, 1.8, vcore, vmem, and PEX) are present on the card but no output or backlight even after sometime (if there is backlight the problem is the memory).
 * The card does not get recognized by MATS.
 * The card works but unreliably (sometimes works but after power cycling it doesn't work)

The BIOS circuit.
Different board manufacturers might use different bios chips, however, they have have the same pinout and work in the same principle.

Markings on the schematic and board could differ from GPU model to another but the circuit is almost always the same.

Here is a reference datasheet.

The resistors for pins 5, 6, and 1 are sometimes on the back of the card close to the core.

Usage.
During initialization, the GPU core pulls pin 1 (CS) low which enables the bios then proceeds to reads the information stored on it, such as the name, clocks, etc.. of the card by communicating through pin 2 (directly connected to the core) and pin 5 (goes through a 33Ω resistor) as shown in figure 2. After that those readings are then sent to the computer.

Identifying Problems.
with an oscilloscope, probing pin 2 and 5 during initialization tells you whether the core is communicating with the bios or not in the first place, if there is complete silence that means the core is not even trying to talk to the bios(probably faulty core or the card has not reached the initialization point). In such case, check whether pin 6 has clock signal using the oscilloscope and pin 1 is being held low during that period. if you have clock signal and pin 1 is going low, the trace going from pin 2 and 5 or the resistor for pin 5 might be damaged. After confirming that is not the case the core is probably faulty. If pin 1 is not going low, check its resistor and trace, if they're fine, either the core is not at the initialization point or faulty.

At this point, if there is communication but the card is still not working, that means the bios chip itself or the content is damaged in some way, you could manually read and write the contents of the bios using a SPI/USB adapter. flash the original bios from TechPowerUp's library of VBIOSes and try again.

if the bios chip is functional and you flashed the correct bios and the core is reading it but the card is still not working then your problem is somewhere else and not the bios.