BTW, for geeks: KT uses
g_file_storage module (with parameter 'removable=y') for exporting it's "disk" as USB Mass Storage device. I've found
some descriptions of it's work. As expected, this command exports diagnostic partition

:
Code:
echo /dev/mmcblk0p2 > /sys/devices/platform/fsl-usb2-udc/gadget/gadget-lun0/file
Command was issued after connecting KT to computer and programmatic ejecting of KT device from computer (USB plug was still in place).
I believe, it's safe to mount exported diagnostic partition on computer for read/write. It's also could be safe to mount exported main partition on computer for read-only. Partition with /var/local should not be exported via this way (as it's mounted by KT OS in read/write mode). The same applies for userstore FAT parition.