Suddenly no upload possible to a SAMD21

Hi, I testing and programming a M0 Pro since a couple of days now..without any problems. No suddenly I'm getting an error all the time.

I didnt even closed the Arduino IDE between the last successful upload .. from on to the other moment it donst work anymore.

What can I do? I'm quite desperate.. Tried to reboot etc without luck.

Appreciate any hints

Open On-Chip Debugger 0.9.0-g932ec70 (2017-02-15-12:33) Licensed under GNU GPL v2 For bug reports, read http://openocd.org/doc/doxygen/bugs.html debug_level: 0 adapter speed: 500 kHz adapter_nsrst_delay: 100 cortex_m reset_config sysresetreq target state: halted target halted due to debug-request, current mode: Thread xPSR: 0x41000000 pc: 0x000028f4 msp: 0x20002c00 ** Programming Started ** auto erase enabled Error: SAMD: failed to erase sector 8. That sector is write-protected Error: failed erasing sectors 8 to 9 Runtime Error: embedded:startup.tcl:454: ** Programming Failed ** in procedure 'program' in procedure 'program_error' called at file "embedded:startup.tcl", line 510 at file "embedded:startup.tcl", line 454 Der ausgewählte serielle Port at file "embedded:startup.tcl", line 454 ist nicht vorhanden oder das Board ist nicht angeschlossen

That's the ouput of debug-mode set to all

pen On-Chip Debugger 0.9.0-g932ec70 (2017-02-15-12:33) Licensed under GNU GPL v2 For bug reports, read http://openocd.org/doc/doxygen/bugs.html debug_level: 2 Info : only one transport option; autoselect 'swd' adapter speed: 500 kHz adapter_nsrst_delay: 100 cortex_m reset_config sysresetreq Info : CMSIS-DAP: SWD Supported Info : CMSIS-DAP: JTAG Supported Info : CMSIS-DAP: Interface Initialised (SWD) Info : CMSIS-DAP: FW Version = 01.1F.0118 Info : SWCLK/TCK = 1 SWDIO/TMS = 1 TDI = 1 TDO = 1 nTRST = 0 nRESET = 1 Info : CMSIS-DAP: Interface ready Info : clock speed 500 kHz Info : SWD IDCODE 0x0bc11477 Info : at91samd21g18.cpu: hardware has 4 breakpoints, 2 watchpoints target state: halted target halted due to debug-request, current mode: Thread xPSR: 0x61000000 pc: 0x000028f4 msp: 0x20002c00 ** Programming Started ** auto erase enabled Info : SAMD: partitioning the first flash page into 8 subpages Info : SAMD MCU: SAMD21G18A (256KB Flash, 32KB RAM) Error: SAMD: failed to erase sector 8. That sector is write-protected Error: failed erasing sectors 8 to 9 Runtime Error: embedded:startup.tcl:454: ** Programming Failed ** in procedure 'program' in procedure 'program_error' called at file "embedded:startup.tcl", line 510 at file "embedded:startup.tcl", line 454 Der ausgewählte serielle Port at file "embedded:startup.tcl", line 454 ist nicht vorhanden oder das Board ist nicht angeschlossen