I've been having trouble with my Canon 550D failing when uploading images. I've had the same issue with 2 different 550D's and multiple USB cables.
Sometimes it will work OK with one or more images then stop working In the attached log it failed on the first one (running looping mode from the Capture window).
I think this might have been the result of a change of Raspberry Pi and insufficient testing with powered hub's. I blew up a pi, my homemade EQ direct cable and a hub several weeks ago trying to add a powered hub into the mix (although at that point the setup was running OK without the hub). Replaced the Pi and EQ Direct cable and mostly tested without a powered hub (that used to work and I have not worked out why I blew up things previously).
The hub I had tried it with during testing appears to be faulty. I'm trying another hub and so far no camera disconnect issues. The downside is the Hub that is in there at the moment is using a 240V power supply. I have a powered 7 port USB 3.0 hub on order so I'll tidy up the cabling for now and see how that goes.
[2020-07-28T15:22:54.533 AEST DEBG ][ org.kde.kstars.indi] - Canon DSLR EOS 550D : "[DEBUG] Setting radio/menu widget eosremoterelease: 2 (Press Full) "
[2020-07-28T15:22:54.681 AEST DEBG ][ org.kde.kstars.indi] - Canon DSLR EOS 550D : "[DEBUG] Failed to set new configuration value (GP result: -7) "
gphoto -7 error means io-error. No idea what causes this. This hints towards a communication problem between gphoto and your camera. It does not look like an Ekos/Indi problem to me.
But that's just my guesswork. I'm not an expert and could be wrong.
Can you reliably trigger exposures by using gphoto only?
Oh, just saw you're using a HUB? That can cause all sort of problems and could very well explain your issues.
My tests yesterday afternoon did not translate into an imaging session last night. Neither 500D seems to want to talk to Indi on the pi at all now. I think my next step is to do some tests back on a laptop and windows to ensure that the USB from the camera still works.
I'd read elsewhere that using a hub with a Raspberry Pi was a good idea to reduce the power load on the Pi itself. On the other hand before my initial experiments with a powered hub it was all working nicely most of the time.
I have camera's talking to the Pi again. I suspect that the USB connectors in the camera are worn enough that the connections were becoming very unreliable (although odd that both started misbehaving around the same time). Squashing the metal surround on the Camera end of the cable appears to have stabilized things (again inside during daylight hours). The external hub is out of the setup for now although at some point I'll need one back in the setup for some additional controllers (roof, Dark/Flat device etc).