at the end of your standard µUSB(2) to USB-A (f) cable, OTG works perfectly bought it & used it w/ MohammadAG's package for Fremantle.
The proper port, USB MicroAB, is compatibly with all the MicroB chargers out there. What's a violation of the industry standard is using MicroB only for USB Host and any such stupid adaptor. But, as usual, I suppose they do this because they do not plan to certify the device for USB Host (again).