Even if I can appreciate a generic answer like yours, my post was a direct request to the author to add Polaris cards in the KnownGpus of this tool
Open source, you can easily add whatever you want ;-)
Cheers!
For me "easily" mean I caused a kernel panic and/or a pci-error on every attempt to modify your code...

Anyway running an unmodified version of your tool I get this output:
./amdmemtweak -i 0 --current
#
NOTHING :-)
I think the problem is I'm using an OSS Driver from debian and not the amd one....
(
https://wiki.debian.org/it/AtiHowTo)
My card (WX-5100) is peculiar and I could not achive a decent install on debian 9 of the amd driver..
Anyway, still reading your code, a brilliant work! (even if I can understand just a 10% of it)
Bye
I also tried running a Radeon Polaris Pro Duo (dual WX-7100) and got nothing when running the tool... I'm obviously doing something wrong or this uncommon gpu just isn't supported, which wouldn't be too surprising. Thought it might be worth a try, simply because like your gpu bios mods aren't particularly practical with this guy and are fairly non-existent on the web.