FM-1 Transporter
1Connect
Plug in the Transporter, then pick its second serial port.
2Loader
Choose wl82loader.bin (jl-uboot-tool). It stays in your browser and the Transporter's RAM.
3FM-1
Power the FM-1 on. Stock V15 enters boot mode by itself. A black-screen unit: switch it off, press Reconnect, then switch it on.
4Backup
Reads the whole flash twice and saves it.
5Write
Choose a full flash image. Only changed sectors in 0x4000–0x92FFF are written and verified.