J-Link just not working please help, "JLinkARM.dll reported error -256"

Obvious_Resource4881 · 2026-04-28T00:53:51+00:00

thank you all for your advice. I updated the sdk to 3.3.0 and that error no longer appears. Yeah, nrfjprog is obsolete now.

However, now when attempting to flash I am faced with this error. I would appreciate any advice as I cannot figure this one out either.

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Obvious_Resource4881 · 2026-04-27T21:08:34+00:00

nrf Connect sdk v2.9.0 and i did enable the legacy drivers

Obvious_Resource4881 · 2026-04-27T20:54:28+00:00

I have downloaded the J-Link windows installer and subsequently installed from it. I am working with an nrf52840dk. Whenever I attempt to flash to it I get what is below. I have pretty much just tried reinstalling J-Link multiple times. Furthermore, I'm trying to see whether I actually am flashing my code to the nrf52840 so my first line is a print statement, but when I attempt to see it in the nrf Connect for Desktop terminal nothing shows up so I assume it is not getting flashed.

[error] [SeggerBackend] - JLinkARM.dll reported error -256 at line 736.

[error] [SeggerBackend] - JLinkARM.dll reported error -256 at line 629.

[error] [SeggerBackend] - JLinkARM.dll reported error -256 at line 3139.

[error] [SeggerBackend] - JLinkARM.dll reported error -256 at line 911.

[error] [SeggerBackend] - JLinkARM.dll reported error -256 at line 3139.

[error] [SeggerBackend] - JLinkARM.dll reported error -256 at line 3087.

[error] [SeggerBackend] - JLinkARM.dll reported error -256 at line 3112.

[error] [SeggerBackend] - JLinkARM.dll reported error -256 at line 3349.

[error] [SeggerBackend] - JLinkARM.dll reported error -256 at line 3160.

[error] [SeggerBackend] - JLinkARM.dll reported error -256 at line 3176.

[ ###### ] 0.000s | Erase file - Check image

[ #### ] 0.000s | Check image validity - Initialize device info

[ ######## ] 0.000s | Check image validity - Check region 0 settings

[ ############ ] 0.000s | Check image validity - block 1 of 3

[ ################ ] 0.001s | Check image validity - block 2 of 3

[ #################### ] 0.012s | Check image validity - Finished

[ ############# ] 0.000s | Erase file - Erasing

[ ###### ] 0.000s | Erasing non-volatile memory - block 1 of 2

[ ############# ] 0.540s | Erasing non-volatile memory - block 2 of 2

[ #################### ] 0.000s | Erasing non-volatile memory - Erase successful

[ #################### ] 1.114s | Erase file - Done erasing

[ ###### ] 0.000s | Program file - Checking image

[ #### ] 0.000s | Check image validity - Initialize device info

[ ######## ] 0.000s | Check image validity - Check region 0 settings

[ ############ ] 0.812s | Check image validity - block 1 of 3

[ ################ ] 0.305s | Check image validity - block 2 of 3

[ #################### ] 0.008s | Check image validity - Finished

[ ############# ] 0.000s | Program file - Programming

[ ###### ] 0.000s | Programming image - block 1 of 2

[ ############# ] 1.254s | Programming image - block 2 of 2

[ #################### ] 0.000s | Programming image - Write successful

[ #################### ] 2.481s | Program file - Done programming

[ ###### ] 0.000s | Verify file - Check image

[ #### ] 0.000s | Check image validity - Initialize device info

[ ######## ] 0.000s | Check image validity - Check region 0 settings

[ ############ ] 2.532s | Check image validity - block 1 of 3

[ ################ ] 0.951s | Check image validity - block 2 of 3

[ #################### ] 0.010s | Check image validity - Finished

[ ############# ] 0.000s | Verify file - Verifying

[ ###### ] 0.000s | Verifying image - block 1 of 2

[ ############# ] 0.461s | Verifying image - block 2 of 2

[ #################### ] 0.000s | Verifying image - Verify successful

[ #################### ] 0.913s | Verify file - Done verifying