I was following this seeed studio tutorial Seeed Studio XIAO nRF52840 on Amazon Sidewalk | Seeed Studio Wiki and I ran into an issue when I got to flashing the firmware. I have a Seeed studio xiao nrf52840 plus and I don’t have a jlink. Is there a substitute to using nRF connect and flashing the aws sample code? What should I do next?
i there,
So, Interesting question. Depending on what the issue is, You could take a fresh Xiao put it in BL mode (convert the Merged.hex and Nordic_manu_hex combined hex into a Uf2 file for a one time drag and drop, but any subsequent changes would require a jlink or at the minimum the EDU to change it. and only if the hex overwrites the bootloader properly if the aderfruit one will even allow it.
Do yourself a huge favor get the nRF52840 DK it has an on-board J-Link debugger as does the nRF54L15DK and can be used for programming and debugging the XIAO. A Segger J-Link debugger is another option, although it’s more expensive. The dev boards and the Nordic $9 BLE dongle gives you complete access to all the tools and the BLE world and can also be used with WIRESHARK as a sniffer.
HTH
GL 
PJ 
I have many threads on here about the DK boards and Using a external probe to work with Xiao. use the magnifier and SWD