maybe a
A500Flash 1M - not really cheap. look for the video at buttom of page - different resellers.
the 5k version come with 512kb flash ram - so you cannot have kickstart 1.3 and 3.1 together ( 256kb + 512kb).
#1) looks like you need one original rom chip, so lets say kick 1.3 - and additionaly you can flash a 3.1 rom image, which you can find on the web and flash it.
or you have original 3.1 rom and can flash 1.2 and 1.3 rom so it may be big enough.
someone else can say something about this switcher?
#1) you may also attache some closeup images of your kickstart swicther - some expert may give you some advice to fix it.