Stratix IV Dev Kit programming failure

[Altera_Forum]

I am having issues loading an SOF onto the Stratix IV Dev Kit. The programmer reports: 

 Error: The instruction register length for the EP4SGX230KF40 device at position 1 in the JTAG chain is unknown Error: Operation failed  For giggles, I queried the available devices on the cable. Interestingly enough, the following excerpt shows what was reported:  Info: Command: quartus_pgm -c USB-Blaster -a Info: Using programming cable "USB-Blaster [USB 7-1.2]" 1) USB-Blaster [USB 7-1.2]  024090DD !  020A40DD !  I am not sure how to interpret this. It looks like somehow the JTAG data is getting corrupted.  I have programmed this card many times before without issue, so I am a little baffled as to what may be going on. Any ideas?

[Altera_Forum]

The device ID looks correct. 

However, the number of USB blaster does not look like correct. You might want to try using external USB-Blaster rather than using on-board-embedded blaster. Usually, if you only have one blaster, it should say [USB-0]

[Altera_Forum]

The USB blaster is identified correctly. I am working on a Linux system, which does not use the same numbering convention as Windows.

[Altera_Forum]

--- Quote Start ---  1) USB-Blaster [USB 7-1.2]  024090DD !  020A40DD !  --- Quote End ---  The exclamation marks in the output indicate that jtagserver (jtagd on linux) was unable to calculate the instruction register lengths of the devices it found.  Since both devices are Altera devices the most likely cause of this is that pgm_parts.txt was not found by jtagd.  Are you launching jtagd manually or letting the tools launch it as usual?  Thanks,  wombat

[Altera_Forum]

jtagd is run as a system service

[Altera_Forum]

wombat, 

 Thanks for the tip. I started poking around after you mentioned the pgm_parts.txt file. It turns out that the jtag configuration somehow got deleted, including the pgm_parts file. After reinstalling, everything looks fine.