I was digging around to see how can I get GDL90 output from Sentry Plus (it is by default encrypted). I was able to find the decryption key earlier but it still requires a separate computer to decrypt and relay the packets. With some help from LLM, I found out that there’s actually a backdoor baked into Sentry Plus (as of 1.0.32).
curl -v -X POST -H 'Content-Type: application/json' \
-d '{"publicGDL90":true}' 'http://192.168.4.1/settings/?action=set'Simply send the request above to Sentry Plus, it’ll start broadcasting standard GDL90 packets that other apps can read. After figuring this out, I searched publicGDL90, and found that it has also been found by others as well.
Theoreticallly, we should be able to bake a custom firmware to emulate Stratux’s vendor extension too but I accidentally bricked my OTA update in the process. 😅 Fortunaely, Sentry Plus actually has a fallback mechanism to boot last known good firmware, but sadly, the OTA update function is a bit broken and rejects all updates now… Going to try getting UART out of it next to recover.