USB mounting dialog

[anarcat]

Current limitation: No GUI for enabling and disabling access to the data partition via USB. It is always enabled and it seems to work reliably, but data could get corrupted if both software on the ereader and another computer were to write at the same time. Maintain a backup copy of your data partition.

copied from the readme file, split off #1

[pazos]

Yes, is a risk to share mounted filesystems through usb without a proper way to check the state of the filesystem. Koreader in kobos is installed under /mnt/onboard, so no luck. But in okreader can be installed elsewhere. Look at koreader/koreader#2597