Put firmware into /srv/tftp on server...
# Get firmware from tftp server to start of RAM -
# this sets env variable ${filesize}
tftp ${kernel_addr} golden.bin
# Write 0xdeadbeef to address 0x450 within binary to set "boot config = STOP_BOOT"
setexpr beef ${kernel_addr} + 0x450
md.l ${beef} 1
mw.l ${beef} 0xdeadbeef
# Now write to flash
sf probe
sf update ${kernel_addr} 0 ${filesize}
reset