The custom bootloader script has been extended.
The set_primary_slot, get_boot_state and set_boot_state functions
are now working.
Remarks:
The fw_sysdata tool doesn't support separate boot fail counters.
For this reason, if the state is queried or set for a slot other than
the primary slot, the script exits with a non-zero return code.
The boot_state is determined by evaluating the boot fail counter.
If the counter is zero, good is returnd. Otherwise, bad is echoed.