write ID to last page of flash
Merge branch 'develop_openstm32' of https://github.com/openwsn-berkeley/openwsn-fw into develop_openstm32
write eui64 at 0x807ffff0 and make page 62~255 written protection
Merge branch 'develop_openstm32' of https://github.com/openwsn-berkeley/openwsn-fw into develop_openstm32