Today I got to a point when I have hooked this to my Nucleo board.

The J6 pinout from years ago seems to be correct. I have wired the SWD pins only and started openOCD installed along with the Ac6 STM32 System Workbench recent version.

/opt/Ac6/SystemWorkbench/plugins/fr.ac6.mcu.externaltools.openocd.linux64_1.12.0.201611241417/tools/openocd/bin/openocd -f getyoo_clickey.cfg -s /home/mm/workspace/getyoo_clickey -s /opt/Ac6/SystemWorkbench/plugins/fr.ac6.mcu.debug_1.11.1.201611241417/resources/openocd/script

For the getyoo.cfg see the attached files.

After openOCD started:

Open On-Chip Debugger 0.10.0-dev-00273-g394abef (2016-11-24-15:12)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
Info : The selected transport took over low-level target control. The results might differ compared to plain JTAG/SWD
adapter speed: 1000 kHz
adapter_nsrst_delay: 100
srst_only separate srst_nogate srst_open_drain connect_assert_srst
none separate
3333
Info : Unable to match requested speed 1000 kHz, using 950 kHz
Info : Unable to match requested speed 1000 kHz, using 950 kHz
Info : clock speed 950 kHz
Info : STLINK v2 JTAG v19 API v2 M v2 VID 0x0483 PID 0x374B
Info : using stlink api v2
Info : Target voltage: 3.259064
Error: BUG: can't assert SRST
Info : STM32F102CBTx.cpu: hardware has 6 breakpoints, 4 watchpoints

Telnet to the port 4444:

telnet localhost 4444

Then read the flash:

> flash banks
#0 : STM32F102CBTx.flash (stm32f1x) at 0x08000000, size 0x00000000, buswidth 0, chipwidth 0
> flash read_bank 0 getyoo.bin 0 0x1FFFF  
device id = 0x20036410
flash size = 64kbytes
wrote 131071 bytes to file getyoo.bin from flash bank 0 at offset 0x00000000 in 2.561862s (49.963 KiB/s)