- With some firmware versions uploading new firmware via serial doesn’t work. The transfer will complete and the unit will reboot but it will still be running the old firmware. FTP transfer work well.
- Some older firmware can’t accept an FTP file transfer of the newest firmware. There is an older version packaged with the new one that can be uploaded first, then it will accept the newer firmware once that intermediary firmware is running. There is no documentation that explains why the intermediary firmware is include but I assume this is why. The specific versions where I ran into it were:
Original firmware: Unknown but ancient
Intermediary Firmware: 2.0.2
Final Firmware: 3.9.2
3. I ran into a weird issue with one where the network on the device would stop working when I had the serial cable plugged in. It only happened immediately after the update and hasn’t happened since.