Error: "Unhandled ProgrammingOptions" when flashing Blinky app to Thingy:91 (not 91X) — possible firmware corruption?

Question

Hi all, 
 I’m working through Lesson 1, Exercise 2 of the Nordic Academy course (uploading the Blinky app to the Thingy:91), and I keep hitting this error: Firmware: C:\myfw
csfund\blinky\build\blinky\zephyr\zephyr.signed.hex Error: Unhandled ProgrammingOptions: [object Object] 
 
 I'm on Windows 11 Pro , using the latest nRF Connect for VS Code , SDK v3.0.2 , and the matching toolchain. The build succeeds, and I’m confident the Blinky app is correctly configured and built for thingy91/nrf9160/ns . 
 However, here’s where I think the problem started: 
 I accidentally followed the Thingy:91X update procedure and attempted to flash using that flow. It partially completed — some files were written — but then it failed. After realizing the mistake, I switched back to the correct process for the Thingy:91 (not 91X), but now I consistently get the error above when trying to flash zephyr.signed.hex using nRF Connect Programmer. 
 I’ve tried:

Reinstalling the SDK and toolchain (v3.0.2)

Rebuilding the application from scratch

The Thingy:91 still shows up in nRF Connect Programmer, but the LEDs no longer light up at all , even in MCUboot mode. Flashing always fails with the same "Unhandled ProgrammingOptions" error. 
 My guess: the failed 91X flashing attempt corrupted the firmware or memory layout somehow. My question: how can I completely reset or recover a Thingy:91 that might have been partially overwritten using the wrong flashing process? 
 Any help would be greatly appreciated! 
 Thanks. 
 The complete error log follows plus a few more screenshots 
 
 21:09:41.574 Initialising the bundled nrfutil device 21:09:41.665 Using the bundled core version for nrfutil device: 8.0.0 21:09:41.682 Using nrfutil-device version: 2.12.3 21:09:41.682 Using nrf-device-lib version: 0.17.81 21:09:41.682 Using nrf-probe version: 0.40.1 21:09:41.682 Using JLink version: JLink_V8.52 21:09:41.683 Your version of SEGGER J-Link (8.52) is newer than the one this app was tested with (8.18). The tested version is not required, and your J-Link version will most likely work fine. If you get issues related to J-Link with your devices, use the tested version. 21:09:41.774 Getting serial port options from the persistent store for THINGY91_D4AD239EE383.pc-nrfconnect-programmer 21:09:41.774 Device connected with the serial number THINGY91_D4AD239EE383 21:09:49.257 Parsing HEX file: C:\myfw
csfund\l1e_2\build\l1e_2\zephyr\zephyr.signed.hex 21:09:49.259 File was last modified at 19/07/2025, 20:48:45 21:09:49.274 Update files regions according to Application core 21:09:49.274 Parse memory regions for file 21:09:54.105 Selecting device with the serial number THINGY91_D4AD239EE383 21:09:54.267 Selected device with the serial number THINGY91_D4AD239EE383 21:09:54.269 Update files regions according to Application core 21:09:54.269 Parse memory regions for file 21:10:01.502 Does not need to be reloaded: C:\myfw
csfund\l1e_2\build\l1e_2\zephyr\zephyr.signed.hex 21:10:06.249 Writing C:\myfw
csfund\l1e_2\build\l1e_2\zephyr\zephyr.signed.hex to device THINGY91_D4AD239EE383 21:10:06.252 MCUboot DFU failed with error: Error: Unhandled ProgrammingOptions: [object Object] 21:10:06.252 Error: Unhandled ProgrammingOptions: [object Object] 21:22:08.147 Does not need to be reloaded: C:\myfw
csfund\l1e_2\build\l1e_2\zephyr\zephyr.signed.hex