I just bought another RPi (for some home automation project) and had some tough time setting it up. The issue was that it constantly died with some error which resulted in Detected aborted journal or rather Remounting filesystem read-only making it necessary to restart and fix the filesystem with fcsk. It was simply impossible to install new packages or update the firmware.
I did some research and the suggested solutions were to buy a better power supply but the supplied power was ok - well, finally I bought a new one, but it still did not work. I tweaked some settings in config.txt but again it did not work.
So now my setup comes into play: I had some USB hub with a USB flash drive connected to it (OS boots from the flash drive). The problem now was that the driver and/or the hub’s chipset was simply corrupt in the sense of being unable to cope with flash drives or rather high-speed devices (no complains about connecting low-speed devices like keyboards).
When I connected the flash drive to the RPi directly it worked without any problems and it was lots faster.
So now the question remains: why didn’t I checked this earlier? Last time (for my other RPi) I had the same issue and there the solution was to buy a USB hub and let it power the flash drive instead of the RPi.
The USB hub was an Digitus DA-70231 with the hardware id 05e3:0608 (Genesys Logic, Inc. USB-2.0 4-Port HUB). This chipset is marked as working and not working here: http://elinux.org/RPi_Powered_USB_Hubs. So from my experience it is working for low-speed devices but not for high-speed devices.