I was about to flash the modded bios for my RX470 (knowing that I have Samsung memory I presumed that the manufacturer was Gigabyte) but after running SRB Polaris, I found out that my card is a Sapphire but with Samsung memory!
@Mattthev being very helpful, will upload in the coming days a modded BIOS for this version of RX470 Sapphire with Samsung memory in
https://mining-bios.eu BIOS was updated, a very straightforward process based on the guide provided.
Observations so far: with timings 1240/2000 and 850v AMD_XMR_STAK 2.2 delivers about 950 H/s per GPU, but after some hours the software is frozen and I have to restart the software not the rig (with the default GPU bios always I had to restart the rig). I think it is a matter of tweaking and testing to achieve stability.
Anyway the good thing is that Claymore is running perfectly without any freezes etc.
I do have noticed though that temperatures are pretty low for AMD_XMR_STAK (47c max) where Claymore is much higher (close to 60c) and also GPU power draw for XMR_STAK is lower vs Claymore (~73v vs ~97v).