I bought an Iconia A1-830 refurbished. I did the flash to 4.4.2 android using some app that Acer supplied. The tablet will not recognize any device connected through the micro usb port (flash drive, keyboard, mouse) using a data cable. I did not check to see if it worked before the OS upgrade.
Running app "USB OTG Checker" showed "Your Device OS has USB OTG API". However, checking for a signal gives an error "System NOT Detect USB OTG Signal". Running app "USB Host Check" shows "android.hardware.usb.host.xml - OK" - "handheld_core_hardware.xml - USB host not enabled" - "tablet_core_hardware.xml - Not found". Attempting to FIX with "USB Host Check" gives error "Could not start su process".
The data cable works fine on another device, so I know it is good. The USB port works fine for charging. I don't know how to proceed from here. Any suggestions?