I installed 2.43 and the fast flash mod on my 84+SE, and I could perfectly replicate the instant goto symptoms reported by the other two users of 2.43 and the fast flash mod. The issue seems to be specific to the 2.43 version of the patch.
Also, the fast flash mod seems to really conflict with zStart, at least on 84+ calculators. This often means that the OS will crash upon startup if run on RAM clears is enabled. If it isn't enabled, opening the zStart app will often either freeze, crash, or let you in only to reveal that the settings are mostly random garbage. This doesn't seem to be specific to any particular OS.
EDIT: And yes, I've been able to replicate both of these in Wabbitemu.