Remember to publish battery calibration so we know AREF (287 or 256) for proper temperature table selection (that also precise at very low temp)
I downloaded EasyTherm and filled in my three reference points:
CLT:
; -2 6500
; 20 2500
; 160 50
IAT:
; 0 5000
; 20 2200
; 100 300
See EasyTherm cltfactor_2400_287.hex and airXfactor_2252_287.hex seems close (for above data) that can be applied to vems.hex with hexpatch.exe (that upload the patched vems.hex and there you go!).
No need to change MegaTune.
See EasyTherm on how to upload table with hexpatch.exe. With your temperature measurements (or sensor resistance at 1..2 temperature points) documented allows others to point to the best ntc curve (like 2700_287). For best result, do the battery calibration and publish the related config variable.
I don't know how the battery calibration is being done. I'll try to find out