You could try connection with my Bluetooth code btferret that avoids the use of bluetoothctl and will show detailed information about the HM10 characteristics.
https://github.com/petzval/btferret
https://github.com/petzval/btferret
Code:
DOWNLOAD btferret.c btlib.c btlib.h devices.txt COMPILE gcc btferret.c btlib.c -o btferret RUN sudo ./btferret FROM btferret command lineEnter b to scan for LE devices - it should find the HM10Enter c to connect and select HM10PAIRING and SECURITY - Enter 1 for yesExperiment with the following to set up the correct security settings - it sounds like this is the problemBONDING - probably 0=Do not bond?PAIRING and SECURITY - probably 2=Pair fixed passkey if passkey is set on the HM10? (or 1=Just Works avoids passkey but may not work)PASSKEY chosen by - 1=Remote serverFixed 6-digit passkey - probably 000000?CONNECTIION COMPLETE TIME 750 to be safePAIRING COMPLETE TIME 2000 to be safeIf the HM10 connectsEnter v to read services. There should be a 0000ffe0-0000-1000-8000-00805f9b34fb primary service.If the HM10 disconnects after a few seconds, the security settings are wrongEnter r/w to read or write to the HM10Enter j to enable notifications from the HM10Enter R to read notifications from the HM10Statistics: Posted by petzval — Sun Mar 23, 2025 12:09 pm