Connect to custom board STM32L053 - STLINK-V2 - SWD
Furthermore, I would suggest to select the right JTAG device, sometimes both an ST-LinkV2 and a ST-LinkV2-1 are present in the SystemWorkbench at the window whose screenshot is attached to this reply. If you select the wrong one, OpenOCD says “Error: open failed” and then eclipse says “Error message from debugger back end:
localhost:3333: The system tried to join a drive to a directory on a joined drive.
localhost:3333: The system tried to join a drive to a directory on a joined drive.”
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