FWIW: I just clocked SSF2 (largest Genny ROM I have loaded) flashing on my v2.0 and I got 33 seconds.
The option my v2.0 pcb has that effects loading time is "Fast Write" on/off. It was on.
Anyone care to test their 2.1 and see if there is a defined difference? If your cart erases before writing, just start timing after the erase step for comparison purposes.