adapted docs to XIAO bootloader file

Author: Daniel Dakhno

docs/FIRST_STEPS.md

@@ -19,7 +19,7 @@ If it doesn't show up at all, follow [this](#generic-board--without-bootloader).
 
 On these boards, you need to update the bootloader first.
 Thus install `adafruit-nrfutil` using pip.
-Then, get THIS FILE and run `adafruit-nrfutil dfu serial -p BOARD_PORT -pkg BOOTLOADER_FILE.zip`.
+Then, get [this file](https://github.com/user-attachments/files/19794746/xiao_nrf52840_ble_bootloader-0.9.2-10-g4329614-dirty_s140_6.1.1.zip) and run `adafruit-nrfutil dfu serial -p BOARD_PORT -pkg xiao_nrf52840_ble_bootloader-0.9.2-10-g4329614-dirty_s140_6.1.1.zip`.
 After, make sure that the .txt on the board shows Softdevice version 6.1.1.
 After, you just need to copy the right file onto the board, which appears as a flash drive.
 The firmware file to search for contains `xiao_ble.uf2`.