The colorful stripes are more likely the decompression routine hammering dff180 (the background color) as a "busy signal" for the user. The Amiga has "chip RAM", which on many unexpanded machines is also the only type of RAM; there are no pre-reserved regions in chip ram; everything (code,data,framebuffers) can be anywhere the programmer wants.

I think OP is (probably?) referring to 8-bit C64 era technology, where framebuffers/video ram are at a fixed location in memory?