Counterexample: The IBM PC was a microprocessor system which does not do it - the BIOS runs from ROM only and sets up the DMA controller for the refreshes. No DRAM, no RAM used.
Excluding the caches, this is how x86 functioned for quite a while, i don't know until when.
Microprocessors don't require internal RAM to bootstrap, because they expose their bus and its simple to map a ROM to the starting address, which can be executed from directly.
Excluding the caches, this is how x86 functioned for quite a while, i don't know until when.
Microprocessors don't require internal RAM to bootstrap, because they expose their bus and its simple to map a ROM to the starting address, which can be executed from directly.