nrf/boards/arduino_nano_33_ble_sense: Update deploy instructions.

ports/nrf/boards/arduino_nano_33_ble_sense/deploy.md

@@ -1,19 +1,23 @@
 ### Update the bootloader
 
-Before deploying any firmware, make sure you have the updated Arduino Nano 33 BLE bootloader, which relocates the bootloader so the softdevice doesn't overwrite it. Please see:
-
-https://docs.arduino.cc/tutorials/nano-33-ble/getting-started-omv
+Before deploying any firmware images, make sure the board is running the
+updated Arduino Nano 33 BLE bootloader (which is relocated to the end of
+the flash), otherwise the bootloader will be overwritten by the softdevice.
+For more information on how to update the bootloader, see the
+[Getting Started with OpenMV/MicroPython](https://docs.arduino.cc/tutorials/nano-33-ble/getting-started-omv) tutorial.
 
 ### Via Arduino bootloader and BOSSA
 
-Download BOSSA from https://github.com/shumatech/BOSSA/ and double tap reset button to enter the Arduino bootloader
+Download the latest BOSSA flash programmer from the
+[Arduino BOSSA fork](https://github.com/arduino/BOSSA/releases/latest).
+Note this version adds support for nRF devices, and must be used with the
+Nano 33 BLE. Double tap the reset button to enter the bootloader, and run
+the following command:
 
 ```bash
 bossac -e -w --offset=0x16000 --port=ttyACM0 -i -d -U -R build-arduino_nano_33_ble_sense-s140/firmware.bin
 ```
 
-Alternatively, a Linux binary can be found here: https://github.com/openmv/openmv/blob/master/tools/bossac
-
 ### Via nrfprog
 
 This board can also be programmed via nrfjprog (with Jlink for example), from MicroPython source repository: