Could not fetch memory size of target devkit: Error: Error occured when get library info. Errorcode: CouldNotOpenDevice (0x4) Lowlevel error: JLINKARM_DLL_ERROR (ffffff9a)

[harry4951]

Hi, I cant get access to my custom nrf52840 board after I click "Erase all" in "Programmer" in "nRF Connect for Desktop". This custom board has been working with me for at least 3 months with the same connection, but suddenly after I clicked "Erase all" last Thursday, I felt that it didnt fully erase the chip but after two seconds it popped up with error mentioned in the title and I cant access it anymore. I searched all the related issues in the forum but none helps. I can get access to the nrf52DK board if I disconnect all the connections with the custom nrf52840 board which means the jlinkob in the nrf52DK is good. Please help to figure it out. Thanks.

Basic info: 

System: Windows 10 Pro

nRF Connect for Desktop v3.7.0 Windows 64bit -> Programmer v1.4.11

nrfjprog version: 10.13.0

JLinkARM.dll version: 7.50a

Setup:

Issues:

I tried nrfjprog --recover and nrfjprog --reset but in both cases got 

ERROR: [SeggerBackend] - JLinkARM.dll reported "-1", "An unknown error.".

I tried Jlink commander also:

Best

/CJ

[Simonr]

Hi again

If you're using the programmer to program "fresh" SoC it should be possible to just do the "Write" option in the nRFConnect Programmer, which shouldn't reset the device before programming it, and should be "safe".

Using nrfjprog and the sectorerase argument should be fine, as it will only erase the flash pages needed by a given .hex file.

Best regards,

Simon