android and external usb devices with multi partitions

Hi All,

I have 2 devices (garmin gpsmap62s and sony prs300 ereader). Both devices when plugged into a windows pc have 2 partitions, the first having system data, the second storing user data.

I have a lenovo 2109 tablet and connect with a OTG usb lead to these devices.

Both devices are seen by the tablet, but on both only 1 partition can be mounted on the android, and you don't get to choose which.

I think this is a general android limitation (not the tablet).

Can someone confirm this and better still, is there any way (non rooting) to solve this?

Many thanks