Bios edit for Polaris

[christiano88]

Hello everyone,

I am trying to do a mod in the bios of my RX card and I have reached a dead end.
What I wanna do is to modify the 1900mhz memory strap to work from 1975, as highlighted below.
I have discovered the timings in the bios with a HEX editor, and also some HEX code between the timings that makes no sense, I have converted it to DEC, and it's gibberish.



If anyone can help, I would really appreciate.

[christiano88]

It's not gibberish, read it the other way.

Edit: I got it, thank you for the tip!

[christiano88]

Also, how can I set the this voltage in the below picture to stick? If I change in PolarisBiosEditor, it still shows 1000mv in WattTool.



Looked in the HEX code and PolarisBiosEditor seems to write the value in the correct location, but for some reason, it doesn't work.

[Q_R_V]

If anyone can help, I would really appreciate.

Take for example 1750Mhz, it's 98AB0200 -> 98 AB 02 00 -> this part is important: 98 AB 02 -> reverse it: 02 AB 98 -> now convert it from base16 to base10 and you will get: 175000. Looks like 1750 Mhz to me

If you want to take 1975 and convert it to hex, you need to it make base10 to base16 conversion (197500 -> 03 03 7C) -> reverse it: 7C 03 03 and voila, ready to paste into the bios.

Also, how can I set the this voltage in the below picture to stick? If I change in PolarisBiosEditor, it still shows 1000mv in WattTool.

Looked in the HEX code and PolarisBiosEditor seems to write the value in the correct location, but for some reason, it doesn't work.

The best way to do it is to add negative voltage offset.

[christiano88]

I figured out with the help of Wolf0 how to change the timing intervals. But the last issue is annoying, how to add negative offset? Read about it on overclockers.net but I wasn't able to understand, didn't have the required hex knowledge. How do I go about changing that 1000mv to 800mv with negative offset? (Probably -200mv, so 6.25mv*32, i have to put that 32 somewhere)

[Q_R_V]

What card model are we talking about? It will be easier for me to answer if you post your specific card model or even factory bios. Isn't that Nitro+ by any chance?

[christiano88]

It is a Nitro+ with samsung memory, 4gb, rx470. Also, would adding a negative offset affect the "P" state voltages? Because I don't want it to touch that, I have defined fixed values there.

[PovertyByte]

I might pick up a Nitro+ 4GB RX470

Posting here so I can get back to this in my post history

[Ambros]

I have a few Sapphire Nitro+ 470 4gb with mixed memories, is it possibile to add voltage offset in every rom in the same way?
I am doing it with Wattool but it's very annoying

[LoneRangir]

I figured out with the help of Wolf0 how to change the timing intervals. But the last issue is annoying, how to add negative offset? Read about it on overclockers.net but I wasn't able to understand, didn't have the required hex knowledge. How do I go about changing that 1000mv to 800mv with negative offset? (Probably -200mv, so 6.25mv*32, i have to put that 32 somewhere)

Can you link to that article, please?

[christiano88]

It's a whole lot of pages on OCN, don't remember the page:
http://www.overclock.net/t/1604567/polaris-bios-editing-rx480-rx470-rx460

[Ambros]

It's a whole lot of pages on OCN, don't remember the page:
http://www.overclock.net/t/1604567/polaris-bios-editing-rx480-rx470-rx460

Yeah, that topic is awesome and very rich, but it's huge.
Do you have any knowledge about how to add a voltage offset that you can share directly here?
Mny of use would appreciate it

[christiano88]

I gave up on finding how to add offset, I found out that it is of no use to me, I wanted fixed values, not offset, and only applied to the I/O memory controller (the one I highlighted above with yellow) and not the "P" states.

[Ambros]

Adding offsets is complicated if your ROM doesn't already have one. Insert it, fix the I2C table length, fix the length of VoltageObjectInfo, fix the offsets of ALL tables that come after VoltageObjectInfo, trim the padding between the regular VBIOS and the UEFI one, such that the size does not change, then fix the checksum.

Thank you for those info. It's the best explanation i've received!
Since the effort is so big I think that change it in WattMan is more effective for my home setup.

[doktor83]

I found this page helpful :

http://www.scadacore.com/field-applications/programming-calculators/online-hex-converter/

[eretron]

So I was playing with Polaris BIOS editor, trying to adjust some stuff in custom BIOS for my 480s 8GB Ref.

What I figured out is that while all the other values I change (Core clock, MEM clock etc...), after flashing OS is using that values, but whatever I enter in GPU voltage, it looks like OS is overriding those values...

For example changing voltage from 850mV to 1100mV has no effect on power consumption from the wall, which is strange...

Why are those values ignored?

I am using ethOS, and ubuntu OS

Thanks in advance

[eretron]

Hm, thanks for answering, I guess I'll leave that to some who is more into that stuff.

But from what I have read on other places, negative voltage offset is what would do the trick, I will try to find out how to edit those in BIOS...

Who knows, maybe I will learn something new along the way