I think USB mount is used for mounting USB flash drives attached through USB OTG.
The essentials. Contains ADB, fastboot and USB drivers from the Android SDK (should work on 8 and 8.1).
To transfer files within TWRP, you need to use adb. Start by installing the driver. To verify for successful driver installation, type in:
It should show you a "List of devices attached" and there's at least 1 item in the list.
Then copy the zip you want to flash into the same folder as adb. Let's say the file is named rom.zip. To "push" it to the phone, use the following command:
adb push rom.zip /sdcard/rom.zip
After it has finished "pushing" the file, just tap "Install" in TWRP and the zip file should be there!
You can now proceed flashing the ROM of your choice.
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