BLE midi device wont keep/store bonding data

[josehdx]

Hello all, will try to be quick and short

I have 2 esp32, one being a newer s3 model and the other one a tttgo display

Both has similar code to create a BLE midi device, but ttgo was suddenly having a different behaviour with what i believe could be the device not storing the bonding info

This affected device every time is rebooted, must be paired again, to any other host (macbook android) and even of the host keep the data, it wont be able to connect unless pairing is done again. as i said, this is happening only with one device and as far as i remember, this affected device was not behaving like this.

does anyone know how to troubleshoot or solve this issue?

Thanks

[josehdx]

I probably found the root cause, but i dont know how to fix. Looks like the mac address is changing after every esp32 reboot. Im not sure what part of my code is provoking this, or if is a device/memory issue. can anyone bring some light?

This issue was also reported here:

https://forum.arduino.cc/t/arduino-bluetooth-midi-to-led/1363764/7

Last post (bottom)

thx

[tttapa]

Are you sure this is the root cause? Are you checking the mac address on the ESP32 itself or on your macbook? The mac address should not change, and I have not observed any changes to it on the ESP32-S3 I have in front of me. You might be seeing different mac addresses because of privacy features in macOS and Android (to avoid bad actors tracking you based on the mac addresses of your peripherals).

I would expect some kind of incorrect BLE or NVS configuration is a more likely culprit here.

[josehdx]

Well, i agree that the mac address should not change as it should me an unique feature, but according to my troubleshooting (see attachment) the affected board (old esp32)is not keeping the identifiers shown after rebooting the board

No issue with esp32-s3

And as you can tell on Arduino forum, similar issue happened to the other user

[tttapa]

I see. My suspicion is that there's an issue with the resolvable private address (RPA) feature in the Control Surface Bluedroid backend. Either it's not set up correctly, or maybe the IRKs are not stored for some reason. Unfortunately, the Bluedroid documentation is quite limited, and I cannot dig into it in detail right now. Since the Bluedroid stack is being deprecated by Espressif, I'm afraid that this is unlikely to get fixed (it just doesn't make sense to spend effort on an unsupported backend). Instead, I would recommend migrating to the supported NimBLE-based backend.

It could be that the Bluedroid problem is easy to fix (e.g. by disabling RPA altogether), in which case pull requests are of course welcome.

[tttapa]

A significant difference between the ESP32 and the ESP32-S3 is that the former still uses the old Bluedroid stack, and the S3 uses NimBLE. Pairing is a bit tricky because it requires writing to NVS. I'm a bit rusty on the details here, so I'm afraid I can't really help with the low-level debugging right now.

[josehdx]

So, would you recommend to downgrade the library and Arduino core version to make it work again?

Thx!