I understand you can't provide IOT TOOLBOX Android source code. But can you tell me what data to send or receive?
After analyzing the data sent by the iot toolbox app, it seems to send the first 15 bytes and then the data created with * .s19.
If you have a QN908x OTA document, please ask for the link where I can download it.
To summarize my requirements.
1. If there is a document with data format for sending and receiving for OTAP, a link to receive the document.
2. If there is no 1 sufficient description of what data should be sent and received (including data format).