Interface: Add warning and hex to erase nrf flash.

Author: microbit-carlos

software/assets/erase-flash.hex

@@ -0,0 +1,18 @@
+:020000040000FA
+:10000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00
+:10001000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF0
+:10002000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFE0
+:10003000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFD0
+:10004000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFC0
+:10005000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFB0
+:10006000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFA0
+:10007000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF90
+:10008000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF80
+:10009000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF70
+:1000A000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF60
+:1000B000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF50
+:1000C000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF40
+:1000D000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF30
+:1000E000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF20
+:1000F000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF10
+:00000001FF

software/interface.md

@@ -126,7 +126,7 @@ You can also flash a full DAPLink image to the <span class="v2">V2</span> device
 
 You will need to register for and download the [**Bootloader Host Application (blhost)**](https://www.nxp.com/design/software/development-software/mcuxpresso-software-and-tools-/mcuboot-mcu-bootloader-for-nxp-microcontrollers:MCUBOOT?&tab=Design_Tools_Tab) from NXP. In the `/bin` folder you will find executables for your operating system.
 
-<div class="alert alert-warning">Please ensure you are using the latest version of blhost, old versions incompatibility with new OS versions can have unexpected results.</div>
+<div class="alert alert-warning">Please ensure the nRF52 flash has been erased before erasing/flashing the KL27 flash. Programmes running on the nRF52 can affect the KL27 internal boot process and stop the kinetis bootloader from running. You can flash <a href="/docs/software/assets/erase-flash.hex">this hex file</a> to erase the nRF52.</div>
 
 ### Enter bootloader mode