How to use OTG cable in Motorola Moto G2?
The device should be visible to use on any file manager that supports OTG (eg. Solid explorer). If your flash drive is not usable anymore, maybe your otg cable, phone or flash drive has/had an issue and burnt the flash. Its usually plug and play unless its an ntfs partition, in which case if your OEM/file manager does not support it properly you may have issues.