possible solution for "PSRAM only"

[nonchip]

in pseudo-C:

int EWRAM_CODE FindMyRompage(){
  static int EWRAM cached = -1;
  if(cached >= 0) return cached;
  static char EWRAM romname_copy[ROMNAMELENGTH];
  memcpy(romname_copy, header->romname, ROMNAMELENGTH);
  static int EWRAM checksum_copy = header->checksum;
  for(int i=0; i<= MAXROMPAGE; i+=0x20){ // probably actually check 0x200 first tho, because psram should only contain us if we just got booted there, since it's volatile
    SetRompage(i);
    if(0==memcmp(romname_copy,header->romname,ROMNAMELENGTH) && checksum_copy==header->checksum){
      cached = i;
      return i;
    }
  }
  return -1; // should never happen
}

first call is gonna be a bit slower than subsequent ones (due to the static cache), and first call needs to be done from the actual rom selected to copy the game's name & checksum from the header, while subsequent ones can just use the cached value to get back to it.