Hi,
I somehow was able to brick my board (probabaly by writing to the flash).
Reset by double-tapping the reset switch is not doing anything :-/
What can I do? any ideas?
Ran
Does it have the LED on? Can the device be seen in the device manager?
Hi, Citric - no to both questions.
This may be the last method. Please refer to it.
That requires speacial hardware, right? Any way around that?
Sorry, as far as I know there is no other way for now.
1 Like
I was also struggling with this and thought the board was toast. The solution was to:
in arduino IDE, go to preferences>>“show verbose output during (upload=true)”
Then upload your sketch. You will see the console trying all of the available ports, when you see it doing this double tap the reset button as fast as possible. The delay between taps has to be very fast.
When the bootloader is lost, the only way to restore it is using the JTAG interface. The lowest cost Segger JTAG is the Jlink EDU mini for about 15 USD, or the JLINK Edu for about 50 USD. You may also consider getting the seeed XIAO expansion base, since it simplifies access to the JTAG pads.
This is as well a useful investment, since it allows to so hardware source code debugging at the board with all the nice features as single step, breakpoints, data inspection, etc.
My XIAO nRF52840 BLE Sense Reset button has gone, is there any option to reset and get into the boot mode
Hi there,
yes, Those Tiny little nubs of a button , come off if you get a little Too Much fingernail action on the reset button. The only other way AFAIK , is the expansion base has a reset button that works for one I have with the same handicap.
HTH
GL 
PJ
1 Like
if the expansion base works then he should be able to manually short the pad
i think you pull the pin to ground
this is for SAMD but i think the procedure is the same
single click for reset and double click for bootloader
Enter Bootloader Mode
Sometimes the Seeed Studio XIAO SAMD21 port may disappear when user programming process fails. we can solve this problem by the following operation:
- Connect the Seeed Studio XIAO SAMD21 to your computer.
- Use tweezers or short lines to short the RST pins in the diagram twice.
- The orange LED lights flicker on and light up.
At this point, the chip enters Bootloader mode and the burn port appears again. Because the samd21 chip has two partitions, one is the Bootloader and the other is the user program. The product will burn a bootloader code in the system memory when it leaves the factory. We can switch modes by performing the above steps.
Yes. 
Expansion board does that exactly…
GL PJ