The BootROM code initiates the boot sequence with the default 4-byte
address octal output fast read command code 7Ch
and the BootROM searches for a valid boot header. If a valid boot header is not
found, the BootROM attempts to load the image using the 4-byte alternate addressing
read command code 13h. If a valid boot header is
still not detected, the basic read command 03h is
tried. If the boot attempt is unsuccessful after the third command, the BootROM
increments the MultiBoot register
(
PMC_MULTI_BOOT
)
read address offset by 32 KB and tries the OSPI command sequence again to locate a
valid boot header. If the OSPI boot mode search limit is reached without a
successful boot, the RCU goes into lockdown and the ERROR_OUT pin is set.
The image search limit for each boot mode is listed in Boot Search Limit.