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, so if you are programming over USB, then we do have an issue with the Thingy v1.0.0 and Windows, that I want to let you know about.  If this is the combination you are using, flashing over USB will not work and I recommend you try using the external debugger you have on hand. 

You are also using the incorrect files for performing DFU over USB. You need to use the files in "images_dfu_hex", or when building yourself, select the file called "app_signed.hex", see the doc here.