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?

[ImagiSam]

Yea, I'm trying to get data out to serial. I was following this advice from one of the Nordicsemi employees. Instead of using usb_uart_bridge source code I was running it from the precompiled firmware. Did I misunderstand is there actually no way of doing the first option?

There are mainly two ways of logging to the computer from the Thingy:91:

1. Through UART: The USB connector on the Thingy:91 is connected  to the nRF52840, and by programming the  usb_uart_bridge sample onto the 52840, the UART log from the nRF9160 can be seen on a serial terminal on the computer.
   • To program the sample, set the switch on the Thingy:91 to nRF52, cd into ncs\nrf\samples\usb\usb_uart_bridge and run west build -b nrf52840_pca20035 && west flash
2. Through RTT: If you’ve connected the 10-pin cable to an external programmer, you can enable RTT logging and see the RTT log in a J-Link RTT Viewer.