Erased everything on NRF52840 Development Kit

Question

Hello guys, 
 
 everything worked fine for me (NRFConnect, Apps, CLI, Building with Segger Studio, Prgramming via NRFConnect Programmer, everything on Win10) but then I was trying to flash a Softdevice on the DK with the "nrfjprog"-Tool and somehow managed to erase everything on the board. Windows was not recognicing it as an COM anymore. By starting the DK with the "IF BOOT/RESET"-Button in bootloader-mode I flashed the Firmeware "J-Link OB-SAM3U128-V2-NordicSemi 170724" on the device. Now it apears as a COM-Port again and the status LED5 is shining again. I can update the Firmware with JLINK to the newest Version: Sadly when I start the NRFConnect and the programmer and try to connect, it doesnt load the "Device Memory Layout" and I can not write, erase or anything else. Even though there is no error displayed. The nrfjprog gives me an Error no matter what command I try: 
 "ERROR: JLinkARM DLL reported an error. Try again."

But as I mentioned befor, I got a second DK here and this one just works as it should with no errors. I already tried to reinstall (JLINK V6.40 now V6.42d, NRFConnect) and update everything to the newest version:

The nRFgo-Tool notices the DK with the correct serial number but prints the folowing message: Recover and enable Pinreset is not possible. 
 
 I guess I deleted something importend (memory structure, bootloader, fimreware..) and need to flash something, but i dont know what. Note that I can choose nRF5x Bootloader, but not nRF5x Porgramming.. 
 
 Running nrfjprog -f NRF52 --recover --log brings the following log:

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 log.log 
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 2019-Feb-16 12:23:14 --------------------------------------------------------------------------------
2019-Feb-16 12:23:14 nrfjprog -e -f nRF52 --log
2019-Feb-16 12:23:14 nrfjprog version 9.8.1
2019-Feb-16 12:23:14 --------------------------------------------------------------------------------
2019-Feb-16 12:23:14 nRF_open_dll
2019-Feb-16 12:23:14 . nRF52_open_dll
2019-Feb-16 12:23:14 . . nRF52_dll_version
2019-Feb-16 12:23:14 nRF_enum_emu_snr
2019-Feb-16 12:23:14 . nRF52_enum_emu_snr
2019-Feb-16 12:23:14 . . nRF52_enum_emu_snr
2019-Feb-16 12:23:14 nRF_enum_emu_snr
2019-Feb-16 12:23:14 . nRF52_enum_emu_snr
2019-Feb-16 12:23:14 . . nRF52_enum_emu_snr
2019-Feb-16 12:23:14 nRF_connect_to_emu_with_snr
2019-Feb-16 12:23:14 . nRF52_connect_to_emu_with_snr
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_emu
2019-Feb-16 12:23:14 . . nRF52_enum_emu_snr
2019-Feb-16 12:23:14 . . nRF52_connect_to_emu_with_snr
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: Firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jan 7 2019 14:07:15
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: Hardware: V1.00
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: S/N: 683558334
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: TELNET listener socket opened on port 19021
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	WEBSRV Starting webserver
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0014ms, 0022ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	WEBSRV Webserver running on local port 19080
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0015ms, 0023ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: returns O.K.
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0015ms, 0023ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_GetHWStatus(...)
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0001ms, 0024ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	There is no generic nRF52 device in J-Link, so we select NRF52832_xxAA.

2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("Device = NRF52832_xxAA", ...). 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	XML file found at: C:\Program Files (x86)\SEGGER\JLink_V642d\JLinkDevices.xml
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0024ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	C:\Program Files (x86)\SEGGER\JLink_V642d\JLinkDevices.xml evaluated successfully.
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	Device "NRF52832_XXAA" selected.
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	Device "NRF52832_XXAA" selected.
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0102ms, 0126ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("SetRestartOnClose = 0", ...). 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x01
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0127ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("DisableFlashDL", ...). 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0001ms, 0128ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("SetDbgPowerDownOnClose = 1", ...). 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x01
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0128ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("ExcludeFlashCacheRange 0x0-0xFFFFFFFF", ...). 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0129ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_TIF_Select(JLINKARM_TIF_SWD)
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0001ms, 0130ms total) 
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_SetSpeed(2000)
2019-Feb-16 12:23:14 . . . nRF52_connect_to_emu_without_snr:	JLink: (0001ms, 0131ms total) 
2019-Feb-16 12:23:14 nRF_read_device_version
2019-Feb-16 12:23:14 . nRF52_read_device_version
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_emu
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_emu:	JLink:	JLINK_IsOpen()
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_emu:	JLink: returns 0x01
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_emu:	JLink: (0000ms, 0131ms total) 
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_device
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_device:	JLink:	JLINK_IsConnected()
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_device:	JLink: returns FALSE
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_device:	JLink: (0001ms, 0132ms total) 
2019-Feb-16 12:23:14 . . nRF52_readback_status
2019-Feb-16 12:23:14 . . . nRF52_is_ctrl_ap_available
2019-Feb-16 12:23:14 . . . . nRF52_read_access_port_register
2019-Feb-16 12:23:14 . . . . . nRF52_coresight_configure
2019-Feb-16 12:23:14 . . . . . nRF52_coresight_configure:	JLink:	JLINK_CORESIGHT_Configure()
2019-Feb-16 12:23:14 . . . . . nRF52_coresight_configure:	JLink: returns 0
2019-Feb-16 12:23:14 . . . . . nRF52_coresight_configure:	JLink: (0102ms, 0234ms total) 
2019-Feb-16 12:23:14 . . . . . nRF52_power_debug_and_system_regions
2019-Feb-16 12:23:14 . . . . . . nRF52_write_debug_port_register
2019-Feb-16 12:23:14 . . . . . . nRF52_write_debug_port_register:	JLink:	JLINK_CORESIGHT_WriteAPDPReg(DP reg 0x02, 0x00000000)
2019-Feb-16 12:23:14 . . . . . . nRF52_write_debug_port_register:	JLink: returns -1
2019-Feb-16 12:23:14 . . . . . . nRF52_write_debug_port_register:	JLink: (0002ms, 0237ms total) 
2019-Feb-16 12:23:14 . . . . . . nRF52_write_debug_port_register:	JLinkARM.dll CORESIGHT_WriteAPDPReg returned error -1.

2019-Feb-16 12:23:14 . . . . . nRF52_power_debug_and_system_regions:	JLinkARM.dll CORESIGHT_WriteAPDPReg returned error -102.

2019-Feb-16 12:23:14 nRF_close_dll
2019-Feb-16 12:23:14 . nRF52_close_dll
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_emu
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_emu:	JLink:	JLINK_IsOpen()
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_emu:	JLink: returns 0x01
2019-Feb-16 12:23:14 . . nRF52_is_connected_to_emu:	JLink: (0001ms, 0238ms total) 
2019-Feb-16 12:23:14 . . nRF52_disconnect_from_emu
2019-Feb-16 12:23:14 . . . nRF52_is_connected_to_device
2019-Feb-16 12:23:14 . . . nRF52_is_connected_to_device:	JLink:	JLINK_IsConnected()
2019-Feb-16 12:23:14 . . . nRF52_is_connected_to_device:	JLink: returns FALSE
2019-Feb-16 12:23:14 . . . nRF52_is_connected_to_device:	JLink: (0000ms, 0238ms total) 
2019-Feb-16 12:23:14 . . . nRF52_unpower_debug_and_system_regions
2019-Feb-16 12:23:14 . . nRF52_disconnect_from_emu:	JLink:	JLINK_Close()
2019-Feb-16 13:39:21 --------------------------------------------------------------------------------
2019-Feb-16 13:39:21 nrfjprog -e -f nRF52 --log
2019-Feb-16 13:39:21 nrfjprog version 9.8.1
2019-Feb-16 13:39:21 --------------------------------------------------------------------------------
2019-Feb-16 13:39:21 nRF_open_dll
2019-Feb-16 13:39:21 . nRF52_open_dll
2019-Feb-16 13:39:21 . . nRF52_dll_version
2019-Feb-16 13:39:21 nRF_enum_emu_snr
2019-Feb-16 13:39:21 . nRF52_enum_emu_snr
2019-Feb-16 13:39:21 . . nRF52_enum_emu_snr
2019-Feb-16 13:39:21 nRF_enum_emu_snr
2019-Feb-16 13:39:21 . nRF52_enum_emu_snr
2019-Feb-16 13:39:21 . . nRF52_enum_emu_snr
2019-Feb-16 13:39:21 nRF_connect_to_emu_with_snr
2019-Feb-16 13:39:21 . nRF52_connect_to_emu_with_snr
2019-Feb-16 13:39:21 . . nRF52_is_connected_to_emu
2019-Feb-16 13:39:21 . . nRF52_enum_emu_snr
2019-Feb-16 13:39:21 . . nRF52_connect_to_emu_with_snr
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: Firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jan 7 2019 14:07:15
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: Hardware: V1.00
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: S/N: 683558334
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: TELNET listener socket opened on port 19021
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	WEBSRV Starting webserver
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0014ms, 0020ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	WEBSRV Webserver running on local port 19080
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0015ms, 0021ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: returns O.K.
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0015ms, 0021ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_GetHWStatus(...)
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0002ms, 0024ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	There is no generic nRF52 device in J-Link, so we select NRF52832_xxAA.

2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("Device = NRF52832_xxAA", ...). 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	XML file found at: C:\Program Files (x86)\SEGGER\JLink_V642d\JLinkDevices.xml
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0001ms, 0026ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	C:\Program Files (x86)\SEGGER\JLink_V642d\JLinkDevices.xml evaluated successfully.
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	Device "NRF52832_XXAA" selected.
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	Device "NRF52832_XXAA" selected.
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0113ms, 0138ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("SetRestartOnClose = 0", ...). 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x01
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0139ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("DisableFlashDL", ...). 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0140ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("SetDbgPowerDownOnClose = 1", ...). 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x01
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0140ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("ExcludeFlashCacheRange 0x0-0xFFFFFFFF", ...). 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0141ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_TIF_Select(JLINKARM_TIF_SWD)
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0002ms, 0143ms total) 
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_SetSpeed(2000)
2019-Feb-16 13:39:21 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0143ms total) 
2019-Feb-16 13:39:21 nRF_read_device_version
2019-Feb-16 13:39:21 . nRF52_read_device_version
2019-Feb-16 13:39:21 . . nRF52_is_connected_to_emu
2019-Feb-16 13:39:21 . . nRF52_is_connected_to_emu:	JLink:	JLINK_IsOpen()
2019-Feb-16 13:39:21 . . nRF52_is_connected_to_emu:	JLink: returns 0x01
2019-Feb-16 13:39:21 . . nRF52_is_connected_to_emu:	JLink: (0001ms, 0145ms total) 
2019-Feb-16 13:39:21 . . nRF52_is_connected_to_device
2019-Feb-16 13:39:21 . . nRF52_is_connected_to_device:	JLink:	JLINK_IsConnected()
2019-Feb-16 13:39:21 . . nRF52_is_connected_to_device:	JLink: returns FALSE
2019-Feb-16 13:39:21 . . nRF52_is_connected_to_device:	JLink: (0000ms, 0145ms total) 
2019-Feb-16 13:39:21 . . nRF52_readback_status
2019-Feb-16 13:39:21 . . . nRF52_is_ctrl_ap_available
2019-Feb-16 13:39:21 . . . . nRF52_read_access_port_register
2019-Feb-16 13:39:21 . . . . . nRF52_coresight_configure
2019-Feb-16 13:39:21 . . . . . nRF52_coresight_configure:	JLink:	JLINK_CORESIGHT_Configure()
2019-Feb-16 13:39:22 . . . . . nRF52_coresight_configure:	JLink: returns 0
2019-Feb-16 13:39:22 . . . . . nRF52_coresight_configure:	JLink: (0103ms, 0249ms total) 
2019-Feb-16 13:39:22 . . . . . nRF52_power_debug_and_system_regions
2019-Feb-16 13:39:22 . . . . . . nRF52_write_debug_port_register
2019-Feb-16 13:39:22 . . . . . . nRF52_write_debug_port_register:	JLink:	JLINK_CORESIGHT_WriteAPDPReg(DP reg 0x02, 0x00000000)
2019-Feb-16 13:39:22 . . . . . . nRF52_write_debug_port_register:	JLink: returns -1
2019-Feb-16 13:39:22 . . . . . . nRF52_write_debug_port_register:	JLink: (0004ms, 0254ms total) 
2019-Feb-16 13:39:22 . . . . . . nRF52_write_debug_port_register:	JLinkARM.dll CORESIGHT_WriteAPDPReg returned error -1.

2019-Feb-16 13:39:22 . . . . . nRF52_power_debug_and_system_regions:	JLinkARM.dll CORESIGHT_WriteAPDPReg returned error -102.

2019-Feb-16 13:39:22 nRF_close_dll
2019-Feb-16 13:39:22 . nRF52_close_dll
2019-Feb-16 13:39:22 . . nRF52_is_connected_to_emu
2019-Feb-16 13:39:22 . . nRF52_is_connected_to_emu:	JLink:	JLINK_IsOpen()
2019-Feb-16 13:39:22 . . nRF52_is_connected_to_emu:	JLink: returns 0x01
2019-Feb-16 13:39:22 . . nRF52_is_connected_to_emu:	JLink: (0001ms, 0256ms total) 
2019-Feb-16 13:39:22 . . nRF52_disconnect_from_emu
2019-Feb-16 13:39:22 . . . nRF52_is_connected_to_device
2019-Feb-16 13:39:22 . . . nRF52_is_connected_to_device:	JLink:	JLINK_IsConnected()
2019-Feb-16 13:39:22 . . . nRF52_is_connected_to_device:	JLink: returns FALSE
2019-Feb-16 13:39:22 . . . nRF52_is_connected_to_device:	JLink: (0002ms, 0259ms total) 
2019-Feb-16 13:39:22 . . . nRF52_unpower_debug_and_system_regions
2019-Feb-16 13:39:22 . . nRF52_disconnect_from_emu:	JLink:	JLINK_Close()
2019-Feb-16 14:06:37 --------------------------------------------------------------------------------
2019-Feb-16 14:06:37 C:\Program Files (x86)\Nordic Semiconductor
rf5x\bin
rfjprog.exe -f NRF52 --recover --log
2019-Feb-16 14:06:37 nrfjprog version 9.8.1
2019-Feb-16 14:06:37 --------------------------------------------------------------------------------
2019-Feb-16 14:06:37 nRF_open_dll
2019-Feb-16 14:06:37 . nRF52_open_dll
2019-Feb-16 14:06:37 . . nRF52_dll_version
2019-Feb-16 14:06:37 nRF_enum_emu_snr
2019-Feb-16 14:06:37 . nRF52_enum_emu_snr
2019-Feb-16 14:06:37 . . nRF52_enum_emu_snr
2019-Feb-16 14:06:37 nRF_enum_emu_snr
2019-Feb-16 14:06:37 . nRF52_enum_emu_snr
2019-Feb-16 14:06:37 . . nRF52_enum_emu_snr
2019-Feb-16 14:06:37 nRF_connect_to_emu_with_snr
2019-Feb-16 14:06:37 . nRF52_connect_to_emu_with_snr
2019-Feb-16 14:06:37 . . nRF52_is_connected_to_emu
2019-Feb-16 14:06:37 . . nRF52_enum_emu_snr
2019-Feb-16 14:06:37 . . nRF52_connect_to_emu_with_snr
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: Firmware: J-Link OB-SAM3U128-V2-NordicSemi compiled Jan 7 2019 14:07:15
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: Hardware: V1.00
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: S/N: 683558334
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: TELNET listener socket opened on port 19021
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink:	WEBSRV Starting webserver
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: (0014ms, 0022ms total) 
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink:	WEBSRV Webserver running on local port 19080
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: (0015ms, 0023ms total) 
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: returns O.K.
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: (0015ms, 0023ms total) 
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_GetHWStatus(...)
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: (0001ms, 0025ms total) 
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	There is no generic nRF52 device in J-Link, so we select NRF52832_xxAA.

2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("Device = NRF52832_xxAA", ...). 
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink:	XML file found at: C:\Program Files (x86)\SEGGER\JLink_V642d\JLinkDevices.xml
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0026ms total) 
2019-Feb-16 14:06:37 . . . nRF52_connect_to_emu_without_snr:	JLink:	C:\Program Files (x86)\SEGGER\JLink_V642d\JLinkDevices.xml evaluated successfully.
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink:	Device "NRF52832_XXAA" selected.
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink:	Device "NRF52832_XXAA" selected.
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: (0112ms, 0138ms total) 
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("SetRestartOnClose = 0", ...). 
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x01
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0139ms total) 
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("DisableFlashDL", ...). 
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: (0001ms, 0140ms total) 
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("SetDbgPowerDownOnClose = 1", ...). 
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x01
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0140ms total) 
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_ExecCommand("ExcludeFlashCacheRange 0x0-0xFFFFFFFF", ...). 
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: (0000ms, 0141ms total) 
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_TIF_Select(JLINKARM_TIF_SWD)
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: returns 0x00
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: (0001ms, 0142ms total) 
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink:	JLINK_SetSpeed(2000)
2019-Feb-16 14:06:38 . . . nRF52_connect_to_emu_without_snr:	JLink: (0001ms, 0143ms total) 
2019-Feb-16 14:06:38 nRF_recover
2019-Feb-16 14:06:38 . nRF52_recover
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_emu
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_emu:	JLink:	JLINK_IsOpen()
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_emu:	JLink: returns 0x01
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_emu:	JLink: (0001ms, 0144ms total) 
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_device
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_device:	JLink:	JLINK_IsConnected()
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_device:	JLink: returns FALSE
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_device:	JLink: (0002ms, 0146ms total) 
2019-Feb-16 14:06:38 . . nRF52_readback_status
2019-Feb-16 14:06:38 . . . nRF52_is_ctrl_ap_available
2019-Feb-16 14:06:38 . . . . nRF52_read_access_port_register
2019-Feb-16 14:06:38 . . . . . nRF52_coresight_configure
2019-Feb-16 14:06:38 . . . . . nRF52_coresight_configure:	JLink:	JLINK_CORESIGHT_Configure()
2019-Feb-16 14:06:38 . . . . . nRF52_coresight_configure:	JLink: returns 0
2019-Feb-16 14:06:38 . . . . . nRF52_coresight_configure:	JLink: (0103ms, 0249ms total) 
2019-Feb-16 14:06:38 . . . . . nRF52_power_debug_and_system_regions
2019-Feb-16 14:06:38 . . . . . . nRF52_write_debug_port_register
2019-Feb-16 14:06:38 . . . . . . nRF52_write_debug_port_register:	JLink:	JLINK_CORESIGHT_WriteAPDPReg(DP reg 0x02, 0x00000000)
2019-Feb-16 14:06:38 . . . . . . nRF52_write_debug_port_register:	JLink: returns -1
2019-Feb-16 14:06:38 . . . . . . nRF52_write_debug_port_register:	JLink: (0004ms, 0254ms total) 
2019-Feb-16 14:06:38 . . . . . . nRF52_write_debug_port_register:	JLinkARM.dll CORESIGHT_WriteAPDPReg returned error -1.

2019-Feb-16 14:06:38 . . . . . nRF52_power_debug_and_system_regions:	JLinkARM.dll CORESIGHT_WriteAPDPReg returned error -102.

2019-Feb-16 14:06:38 nRF_close_dll
2019-Feb-16 14:06:38 . nRF52_close_dll
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_emu
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_emu:	JLink:	JLINK_IsOpen()
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_emu:	JLink: returns 0x01
2019-Feb-16 14:06:38 . . nRF52_is_connected_to_emu:	JLink: (0001ms, 0256ms total) 
2019-Feb-16 14:06:38 . . nRF52_disconnect_from_emu
2019-Feb-16 14:06:38 . . . nRF52_is_connected_to_device
2019-Feb-16 14:06:38 . . . nRF52_is_connected_to_device:	JLink:	JLINK_IsConnected()
2019-Feb-16 14:06:38 . . . nRF52_is_connected_to_device:	JLink: returns FALSE
2019-Feb-16 14:06:38 . . . nRF52_is_connected_to_device:	JLink: (0001ms, 0258ms total) 
2019-Feb-16 14:06:38 . . . nRF52_unpower_debug_and_system_regions
2019-Feb-16 14:06:38 . . nRF52_disconnect_from_emu:	JLink:	JLINK_Close()

___________________________________________________________________________________________________________________ My Setup: 
 Windows 10 nRFConnect 
 nrfjprog 9.8.1 
 JLINKARM 6.42d 
 nRF SDK 15.0 
 SDK for Thread and Zigbee

I tried: 
 - Using different USB Port 
 - Using different cable 
 - deinstalling the DK and driver in Windows Device-Manager 
 - reinstalling the complete Toolchain (Segger JLink, nRFConnect, nRFgo, nRFCommand-Line-Tools 
 - updating Firmware on the DK with JLINK 
 - Using the second DK and everything works just fine..

What is missing on my board to be in factory/default settings? Thanks for your help, sorry for my lack of knowledge.

gabbas1 · Accepted Answer

I found out what was the problem: I used the DK with the Power Profiler Kit and so I cutted "SB40". Now I dettached the Kit but didn'n resoldered SB40 or attatched a jumper on P22. Totally forgot about that.. 
 Now i attatched the jumper and everything works fine again.