Ok, it looks like MTU has been negotiated to 500. All is fine. GATT ERROR (0x85) This error is nasty, because its unspecific error. Ive got it sporadically few times and never knew why. Also i couldnt find any satisfying info on internet about that error. This explains why its followed by TIMEOUT. A...

flash read err, 1000

This usually means that nothing is flashed. You can flash any example or app.

0x02 - MTDO (GPIO15) .... 15 (MTDO) If driven Low, silences boot messages printed by the ROM bootloader. Has an internal pull-up, so unconnected = High = normal output. As you can see its used to silence boot messages and can be either LOW or HIGH. Its very unlikely it will prevent booting unless t...

Hi,
whats wrong with internal esp32 WDT?

I dont remember correct numbers now, but its similar speed to UART flash with 115200.

so one other possibility would be to use classic bluetooh on the ESP32-WROVER-B, right?

You can use wrover or wroom module. All but ESP32S2 modules have bluetooth classic and BLE.

So my question is, if I have 3 sensors all with active LOW interrupt. I want to wake the ESP32 from deep sleep and also know which sensor has triggered an interrupt. What should I do?

Add logic inverter (NOT gate) and use any high?

1) its a big file, 2) not possible with BLE, with this size it will take 5+ minutes, 3) i am using this plugin https://ionicframework.com/docs/native/bluetooth-le, If you want to have better throughput its advised to use classic bluetooth, maybe this plugin: https://ionicframework.com/docs/native/bl...

Can you confirm in nRF connect logs that MTU has been negotiated and confirmed?
Remember you have to call this before connect (or at least before central asks MTU):

There is few aspects you have take for consideration: 1) file size - what means big file, (for example i am sending 1,3MB+ file over BLE in OTA over BLE), 2) what speed you are expecting, 3) what framework you want to use for android/iOS, for example i found that ionic cordova and flutter does not s...