Hi, is there a software way to put the Xiao BLE Sense in bootloader mode so that it accepts a UF2 package ? Or is double pressing the reset button the only way ?
If I remember correctly, when flashing with the Arduino IDE it is not needed to double press the button (but I might be wrong on that one), so I as wondering.
Thanks in advance.
Nicolas Goualard
Hi there, nicoguo and Welcome here,
AFAIK there is no software entry into the Bootloader mode, someone else may comment as well. The Arduino IDE does a reset and drops the baud rate and holds the DTR low causing a reset with GPIO-1 low and enters BOOT mode.
There is OTA updates, the routine in the end does the same thing using the Flash memory set a side.
HTH
GL 
PJ 
Hey, thanks for the answer!
It turns out you can! 
The Xiao BLE boards are using the Adafruit nrf52 bootloader, and the documentation for that:
describes the different ways to put the device in Bootloader mode.
From what I gathered in the boards file in that same repo, the FRST pin is connected to a button on the expansion board for Xiao boards, so I ended up trying the GPREGRET + restart method which was working for me.
Hope it helps someone else in the future.