I wanted to post an update about the problem. I could not resolve the issue myself although I tried everything suggested, so I asked for a warranty claim. After 2 weeks, they gave me a brand new H2O v2!
So I would recommend anyone facing this weird issue to do the same.
Note: My old H20v2 was edition 1 (as explained here
https://www.mobileread.com/forums/sh...&postcount=223) and the new one is edition 2.