Xbox-Linux (Michael Steil & Franz Lehner) explains that their are some risks involved if you plan to split your v1.0/v1.1 TSOP in several banks. If you added one switch between A18 of the flash IC and GND and one switch between A19 and GND to make a splitted TSOP it might cause problems with some bios mixes because the "Xcodes that get executed do not belong to the active image - actually the Xcodes from bank 0 get executed always, no matter what bank you select."

They also speak about the alternative solution to connect A18 and A19 resp. either to GND or to Vcc ... some sources told us this solution will work just fine, but in the article they say "it is quite likely that this will make your MCPX explode! (not sure what they mean with that).

Why you shouldn't do TSOP Splitting:
Many people use four different ROM images in their 1 MB v1.0 or v1.1 flash - please don't do this. Read why here.