Thingy 52 - can't connect - thingy keeps restarting

[Jakub J.]

Hello

Recently, after a long time not using my Thingy52,  I encountered a problem with it. I cannot connect to the device. Earlier it worked fine (can't remember if it was prior to the fw update or something).

Tried reflashing it with the newest software (the oldest available too), I uninstalled and installed the thingy app on my android, tried connected with nRF Connect.

Whenever I try connect to the device, the green led turns on for a moment and then blue breathing led comes in. It seems that as soon as I connect to the device, the thingy restarts itself.

Any ideas?

[Bjørn Kvaale]

The green light on the Thingy device means it is already connected to another Bluetooth device. When it turns blue, this is the default mode for the Thingy. I also believe this means that the Bluetooth device that is connected to the Thingy is not currently connected (i.e. might be turned off). 

How did you flash the newest firmware to the Thingy? Via an nrf52 DK & a SWD cable? Are you able to connect to the Thingy device & change the color of the LEDs? Or does the Thingy restart every time you try to connect? This case might be useful.

[Jakub J.]

I flashed Thingy using an SWD cable and Segger J-Link Plus.

Problem is I am not able to connect at all.  When I'm pairing the Thingy with Thingy Android app, as soon the device got paired and I am able to set its name I get a message that device has disconnected. Later I am not able to reconnect.

Both during initial connection and later when trying reconnecting there is one flash of green light and then it seems to restart (blue light is flashing. I guess this is my latest LED Setting)

I checked the privileges on my android and everything is alright. 

[Bjørn Kvaale]

Did you download this hex file to the Thingy (v2.1.0)? How did you flash the FW to the Thingy (i.e. did you use nrfjprog or nrf go studio)? Do you by any chance have the Lightblue Explorer app installed on your phone? Which phone are you using?

[Jakub J.]

I flashed exactly that version using nrfjprog.

I do not have Lightblue Explorer app installed.

Today just out of cuiosity I tried connecting to the thingy via PC nrfConnect application using nrf52 PCA10040 devboard as a radio dongle. It worked! So clearly it is a problem with connecting to the phone.

I'm using Samsung Galaxy A3 (SM-A320FL) with Android 7.0. There is no problem to connect to other Nordic Bluetooth devices using nrfConnect installed on that phone.

[Bjørn Kvaale]

There could be something fishy happening with the Samsung A3 phone. We have noticed that sometimes the A series from Samsung breaks the Bluetooth spec, which might lead to this issue (see link). Could you try downloading the nrf sniffer software & using your nrf52 pca10040 as a bluetooth sniffer & sniffing what happens when you try to connect your Samsung to the Thingy device? You can post the sniffer log here & I will take a look at it. 

Do you another phone you can test with to see if you can connect to the Nordic Thingy:52 device?

[Jakub J.]

connect.pcapng

connect2.pcapng

Initial.pcapng

Initial.pcapng shows traffic during initial connection with thingy.
connect.pcapng and connect2.pcapng shows traffic after the thingy was found and added, when I try to connect to it.

I'll try to borrow some other phone to try it out over the weekend.