I performed last week the upgrade my Uniti 1 (With the later 24/192 streaming board) from version 4.6 to 4.9. At the end of the ARM upgrade phase, the update failed with “ Communications Failed” reason. In details, the upload stopped at 99%.
I tried to perform new upgrades in 4.4, or 4.6 with 2 different computers in order to have different serial ports (Integrated COM port, usb-Serial converter) and I got the same failure.
My NaimUniti is now no more operationnal.
Do you have any idea of the reason of this failure and how to solve this issue?
I would also contact Naim support as the instructions on the error screen advise. It’s un likely given you have tried a few times you will be able to resolve this on your own.
The early Units had an electroytic cap on the RS232 IC’s internal regulator. It was found that this could cause data corruption, especially when cold. It was updated to a ceramic capacitor in 2010.
It could cause issues similar to how you describe.
Try leaving the unit powered up for an hour before trying the update to allow it to warm up. Alternatively, heat the area around the serial port using a hairdryer - the cap lives just behind the socket.
I tried the first proposal and let the unit powered up for all the night. I launched the upgrade and I got the same result at the end of the ARM FW upload with a failed upgrade.
Then I heated the area around the serial port and launched the upgrade. I really noticed an improvement during the FW upload (less than 10 min instead of 40/50 min to reach 99%). Unfortunately at 99% I still got 5 consecutive retries and the upgrade was aborded.
At last, I monitored the traffic on the serial port during the upload and noticed that the last data block (probably the last one because it is really smaller than the previous ones) sent by the laptop is considered as “NACK” by the Naim unit, and after 5 retransmissions with a “NACK” reply, the link is released.
I do not see what could have an effect on this last block to consider it bad.
I got a feedback from Naim support and I tried the reset of the unit, but without success. The Naim support was anyway not very optimistic on the result of the reset.
I finally opened the Uniti, disconnected the flat ribbon cable on the streaming board for the host connection for a test and launched the ARM upgrade, while warming the back of the unit. Surprisingly, the ARM upgrade ended successfully. And after reconnection of the flat ribbon cable and a power off/ power on circle , I could finalize the upgrade. The unit is now in 4.9.
I don’t have the final root cause (maybe this flat ribbon cable not correctly inserted ?), but at least now the unit is fully operational.
