Thingy:91 not connectable. LED is off but can program

[ImagiSam]

I was working with the Thingy:91 trying to get into into a serial printing state. I tried to updated the modem and firmware using the nrf Programmer. When updating the modem it hangs at 100%. Programming the device seems to succeed but now the LED is not flashing and the Thingy:91 is not connectable

I have tried downloading the following programs but it doesn't run:

• thingy91_ltem_2020-04-29_bc7ade8b.hex
• merged.hex (local based on 1.3.0)
• merged.hex (sourced from here https://devzone.nordicsemi.com/f/nordic-q-a/58484/thingy91-wont-boot-merged-hex-works-on-nrf9160-dk)

It seemed like it was working fine until the modem update which didn't work. 

The other thing is (once it starts working) that if I need to get it printing output to a serial terminal I need to flash:

• thingy91_ltem_2020-04-29_bc7ade8b.hex on the nrf91
• thingy91_nrf52_usb_uart_bridge_2020-04-29_bc7ade8b.hex on the nrf52

And I do that by flipping switch on device, then flip to other and flash and then it should run?

[Heidi]

Hi!

My initial question is: Are you using an external debugger or programming over USB? 

If you're using an external debugger, it looks like you're doing everything correctly, so I would be interested in the error message from the programmer application. If you're trying to program over USB using the bootloader, then it doesn't look like you're putting the device in serial recovery mode, which might be your issue. 

Best regards,

Heidi