Now that we got picture quality to acceptable level with fw 2.4
( Roav Dash Cam C1 Pro image quality ),
i can give you some other thoughts about the device.
There is quite a lot of glare from the windshield. I ordered a bunch of small CPL-filters from china and hoped for the best for some of those to fit my camera. Slightly over sized filter (for another dashcam with square lens body) stuck on nicely with double sided foam tape, so that the foam forms a partial ring outside the lens body. Side of foam, mostly without glue, is what keeps it on. I’ll need to take it off some sunny day, to get actual difference on video. I think it helps a little, but i can still see parts of dash glaring some times.
App wont always play videos, or let me download those to my phone. I waited for minutes and it slowly starts to get gps and acceleration sensor data on the screen, but that loading thingy just spins forever and video never starts. My investigations are still quite inadequate, but i’m starting to believe that temperature has something to do with it. I have successfully watched/downloaded videos on a rainy days, but have faint memories about it mostly failing when its been sunny. I live in Finland, where its rarely hot, so it seems odd that i could get to problems with it 
Camera has been very hot though, aluminium sides almost too hot to touch, when i had to leave my car on a sunny spot. Does these cameras really handle actually hot climates?
Downloading videos to phone happens on the foreground of the app, so i have to wait and watch really boring progress bar. Could it be another process and in background, so i could check another videos (and yes, slow the download even more) to be ready with next download when earlier is ready, or even better, add files to cue. Now i cant even exit the app while it transfers, as it immediately closes the connection. There are probably some limitations with multiple network connections on android, but at some level it should be possible to use 4G while wifi is transferring, as we can share a wifi-hotspot to other phones. Even if i cant get network connection, there are many things i could do on my phone while waiting for videos to transfer. Even watching the file i am transferring would be better than just the progress bar, as the transfer speed seems to match live video quite closely.