i love the clip! … extra words to trick the man… bla bla… what da?
Hi there,
So , And for those JLink Jockey’s out there. Just connect under reset at speed = 1000 or less I used at 500hz on a very stubborn one I was I2S messing with in the Round Display and did not want to halt or erase… after a low speed strafing run it cracked it open like an egg. Able erase , write(loadfile) AOK. (keep the leads REAL short)
connect
device type
SWD
Speed- 1000k (defualts to 4000k) if it works but won’t verify, drop it to 500K and " Roberto’ is your Uncle"
Halt
Erase
Loadfile c:\Your\good\stuff.hex
(optional)…
Regs (cpu registers print out)
Go (after a halt, sanity check it’s alive and working)
EXIT … Your work is done here, Enjoy the Restored Xiao 
HTH
GL 
PJ 
Looks like this,
Hi! Thanks for posting this solution.
I had a custom board with built-in cmsis debugger and it turns out that, every chip out of the factory is enabled with access port protection and requires j-link to flash. I was able to erase the chip and flash it with the cmsis.
I was very close to buying the J-link / DK 
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Mass erase support in OpenOCD has already been added in the latest SDK. It now checks the lock status and automatically unlocks the device before flashing.
4 Likes