0xAA88 bytes are copied from 0x2508 to 0x810484

IRAM usage:

800000:	everything from here to 81047C is zeroed out
800004: 1 written here
800008: var set to bottom of SVC stack
80000C: var set to top of SVC stack
800010: 16-bit checksum of copy-to-RAM block, before copy
800012: 16-bit checksum of copy-to-RAM block, after copy
81047C:	bottom of init stack (0x400 bytes)
810484: first byte used by copied code block
81AF0B: last byte ""
81AF60: initial SP for abort and undef
81AFF8:	bottom of SVC stack
81B454: initial SVC SP
81B4D4:	initial IRQ SP
81B6D4: initial FIQ SP