After loading the CCP it is transported to E000 in bank1. For this the bank is changed to io1 with 4k shared.
During this action the interrupt handler is enabled and there is a chance the interrupt fires while the wrong banking is in effect.
This trans$ccp should be surrounded with "di" and "ei".
(I ran into this problem while adding a U2 drive-image handler to the drive table, this causing a hangup in the trans$ccp.)
c128cpm/cpm/cxio.asm
Line 703 in bf6a9c4
After loading the CCP it is transported to E000 in bank1. For this the bank is changed to io1 with 4k shared.
During this action the interrupt handler is enabled and there is a chance the interrupt fires while the wrong banking is in effect.
This trans$ccp should be surrounded with "di" and "ei".
(I ran into this problem while adding a U2 drive-image handler to the drive table, this causing a hangup in the trans$ccp.)