SMC error after battery change

I changed my dying battery with one from ifixit. After putting in the new battery I reset the PRAM and SMC and turned the laptop on. From then on, the fans blew at full power constantly and kernel task was crippling the CPU. Diagnostics showed error PFM007 - there may be an issue with the SMC. The old battery was destroyed during removal, so I couldn’t try putting it back in. I was sent a new battery from ifixit, but the problem persisted. SMC and PRAM were reset numerous times, nothing changed. I installed istats to see if anything looked out of the ordinary, everything looked fine except missing temperature data from the palm rest.

So my questions are - is it possible to reflash the SMC to an earlier firmware to see if the problem persists;

and can the palm rest temperature sensor be causing these issues, and where is it located (I read somewhere that it’s part of the trackpad ribbon cable)