No boot sequences

(being annoyingly pedantic) technically there is a boot sequence: the Gameboy logo. on the DMG there's a little blob of code from 0x0000 to 0x00ff that clears some memory, sets up the screen, reads the logo from cartridge memory and scrolls it. the loader only jumps to the game if the logo is byte-identical (the idea being that unlicensed games could be sued for trademark infringement.)

on the GBC the loader is a little beefier but mostly the same.

t. made a horribly broken FPGA core for the DMG that got just far enough to load the Tetris intro