Updating old DCC On Board (version 46)

[OlderCoder]

Hi all,
I bought an old n-scale F7 with DCC On Board.  It does run, but I was disappointed to find that the support for speed-matching is virtually non-existent. Only CV2 (starting voltage) is supported.  Speeds 1-8 are essentially the same, while faster speeds do work.  Has anyone updated the decoder to something better, or is the motor not good enough to bother with?

Thanks in advance!