I would like to share my experience in case it helps other ASI2600 P25 users.
For many months I was fighting with random image download failures on my ASI2600MC Pro P25.
Symptoms
The problem was intermittent and very difficult to diagnose.
Sometimes the camera would work perfectly for a whole session, and sometimes it would start failing almost immediately.
In NINA I would get:
ZWO Driver Error
Error retrieving image data from camera
Camera download failed
In ASIImg I noticed missing frames.
The most interesting part was that the problem could appear or disappear after reconnecting the camera. One connection could be perfectly stable, while the next connection could immediately start producing download errors.
What I tested
I tried almost everything:
different 12V power supplies
different USB cables
direct connection to the PC (no hub)
Intel NUC and a separate laptop
cooler ON and OFF
different USB Traffic / USB Limit settings
latest ZWO drivers
latest ASCOM drivers
NINA Native driver
NINA ASCOM driver
ASCOM seemed a little more stable than the native ZWO driver, but the problem still occurred.
SDK Log Errors
Each time the failure happened, the ASICameraSDK log contained similar messages:
1 wait for xfer error:997
2 data length wanted: 52183296
3 data length got: 0
4 Data in cache is invalid, could not reload
5 EXP_FAILED
6 ResetDevice
The camera was clearly exposing correctly, but the frame download failed.
Important Observation
I also use several other ZWO cameras on exactly the same equipment:
ASI294MM Pro
ASI178MM
ASI462MC
None of them ever showed similar behavior.
This made me suspect that the issue was specific to the ASI2600MC Pro P25.
FPGA Update
While investigating, I discovered the official ZWO Firmware Upgrade Tool which contains FPGA updates for P25 cameras.
Before the update my camera reported:
FPGA Version: 1.2.0.2
I updated the FPGA using:
FWUpdate_Windows_v1.4
and the FPGA version became:
FPGA Version: 5.6.5.6
Current Results
After the FPGA update I started repeating the same tests that previously triggered the problem.
So far:
multiple NINA imaging runs
native ZWO driver
repeated camera reconnects
USB 3.0 direct connection
and I have not seen a single download failure yet.
Before the FPGA update, I could often trigger the problem after only a few reconnects.
Conclusion
It is still too early to declare victory because the problem was random and intermittent.
However, at the moment the camera appears significantly more stable after the FPGA update.
I will continue testing and will update this thread if the errors return.
If you have an ASI2600 P25 and are experiencing:
Camera download failed
Error retrieving image data from camera
xfer error 997
random dropped frames
it may be worth checking your FPGA version and looking into the latest FPGA update provided by ZWO.
I hope this helps somebody.
Clear skies!
