my question still stands - is there a bit-file to be found that configures the P1 the same way as P2 is with the default firmware? am i assuming correctly that the P1's pins still all should work fine?
Most standard firmware duplicates the P2 pinout on P1 (but you would have to edit the hal file to change the stepgen and GPIO numbers)
Unfortunately, if you damaged a bus switch (U4 or U6 which typically bear the brunt of excess/reverse voltage damage) ,
it will affect both connectors. These are cheap chips but tricky to replace unless you are used to SMT repair.