Program a SAMD21 with OpenOCD and a JLINK

openocd-samd21.cfg

# Program a SAMD21 part with a bootloader using a JLINK / J-LINK
# 0a. Wire up your device with SWD & SWC pins to JLINK
# 0b. Also wire up Gnd and Power to Gnd & VTref on JLINK
# 0c. And separately supply power to device 
# 0d. Iif you don't have openocd installed, then "brew install openocd"
#
# 1. Put this file in a directory
# 2. Get a samd21 bootloader file.bin and put it in this directory renamed as "bootloader.bin"
# 3. Unplug and replug in the JLINK (to reset it)
# 4. Then do "openocd -f ./openocd-sams21.cfg" and stand back

source [find interface/jlink.cfg]
transport select swd
source [find target/at91samdXX.cfg]
init
reset
halt
program bootloader.bin verify reset
shutdown

this specific script from https://hackaday.io/page/5997-programming-a-samd-bootloader-using-jlink-linux

but also see:

• https://gist.github.com/todbot/6b8da4bed3545313ae976be6be7ffc40
• https://github.com/todbot/samd21-programming-notes

Another way. Uses load_image instead of program. Put this in openocd-samd21-way2.cfg and do openocd -f ./openocd-samd21-way2.cfg:

source [find interface/jlink.cfg]
transport select swd
source [find target/at91samdXX.cfg]
init
reset
halt
load_image bootloader.bin 0
verify_image bootloader.bin 0 bin
reset run
shutdown

Also, if you get the error:

Error: SAMD: NVM lock error

then add this line after the halt line:

at91samd bootloader 0

The Dec 6, 2020 Hackaday link is dead.

The Dec 6, 2020 Hackaday link is dead.

The link is good but hackaday.io was having issues recently. Perhaps that's what you were experiencing.

Thanks. The link now works. Too bad that its content has an important dead link that points to https://roamingthings.de/posts/use-j-link-to-change-the-boot-loader-protection-of-a-sam-d21/. Fortunately, the relevant info of the now dead site was extracted and listed in the Hackaday site.