I have discovered an odd problem using BOOT with different flavors of XB like RXB and MECHATRONICS for examples.
Using RalphB's excellent FinalGrom I have loaded up RXB and selected an Extended basic program from my my Boot menu - after doing so BOOT complains No Ex-Basic, press any key.
Same thing happens when trying the Mechatronics version. Others may as well?
Super Extended Basic works fine, as well as TI's v110.
Is BOOT looking for a specific version of XB?
I am using V 12/13/89 version of BOOT.