arduino-ble-led example doesn't run

[x3e]

Hi all,

I'm trying to run the arduino-ble-led example. I'm using the waveshare_ble400 board. The only modification that I made to the project is to select an stlink tool:

platform = nordicnrf51
framework = arduino
board = waveshare_ble400
lib_deps = ${common.lib_deps}
build_flags = ${common.build_flags}
debug_tool = stlink
upload_protocol = stlink

The project builds fine and flashing seems to work, but the device doesn't really do anything (no serial output, no LEDs etc.). If I try to debug and pause, the device is always at 0x00000596, maybe that indicates that the softdevice is incorrectly flashed?

The standard blink example works fine, but as soon as I add the softdevice with build_flags = -DNRF51_S130, I get the same behaviour: No blinking LED on the board anymore, and debugging always pauses at 0x00000596.

Any help is appreciated.

Attached my (full) build folder.
buildresult.zip

And the log for uploading:

Checking size .pio\build\waveshare_ble400\firmware.elf
Advanced Memory Usage is available via "PlatformIO Home > Project Inspect"
RAM:   [          ]   3.3% (used 1076 bytes from 32768 bytes)
Flash: [=         ]   6.2% (used 16336 bytes from 262144 bytes)
Building .pio\build\waveshare_ble400\firmware.hex
Configuring upload protocol...
AVAILABLE: blackmagic, jlink, nrfjprog, stlink
CURRENT: upload_protocol = stlink
Uploading .pio\build\waveshare_ble400\firmware.hex
xPack OpenOCD x86_64 Open On-Chip Debugger 0.11.0+dev (2021-10-16-21:19)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
debug_level: 1

0x4000
target halted due to debug-request, current mode: Thread 
xPSR: 0xc1000000 pc: 0x000006d0 msp: 0x000007c0
** Programming Started **
Warn : Adding extra erase range, 0x000007c0 .. 0x000007ff
Warn : Adding extra erase range, 0x0001efd0 .. 0x0001efff
** Programming Finished **
** Verify Started **
** Verified OK **
** Resetting Target **
shutdown command invoked
=============================================================================== [SUCCESS] Took 9.59 seconds ===============================================================================

Environment       Status    Duration
----------------  --------  ------------
waveshare_ble400  SUCCESS   00:00:09.589
=============================================================================== 1 succeeded in 00:00:09.589 ===============================================================================
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