Hey fellow Android tinkerer, I get where you're coming from—rooted your old LG K120, tried an OTG activation app but it didn't stick, and you don't want to risk bricking it with a custom ROM. Let's go through some safe, workable options to access your microSD without prying open the back every time:

Option 1: Force-Enable OTG via Rooted Build.prop Edit #

Since your phone might have the hardware for OTG but it's disabled at the system level (the app you used might only toggle a surface-level setting), we can tweak the system config file to unlock it. This is low-risk as long as you back up first:

• Install a root-enabled file manager (like Solid Explorer or FX File Explorer—look for one that explicitly supports root access)
• Navigate to /system/build.prop, make a full backup of this file (copy it to your internal storage or cloud first—this is critical if something goes wrong)
• Edit the file and add these lines at the end (or modify existing ones if they're already present):

  persist.sys.usb.config=mtp,adb,otg
  ro.usb.otg.support=true
  ro.sys.usb.otgcontroller=true
  

• Save the changes, restart your phone, and plug in your OTG USB drive/card reader. If it works, great! If not, restore your backup build.prop to revert everything.

Option 2: Wireless microSD Reader (No System Mods Needed) #

This is the safest, most hassle-free option since it completely bypasses your phone's OTG limitations:

• Grab a WiFi-enabled microSD card reader (small, portable devices that you plug your microSD into—they broadcast their own WiFi network)
• Power the reader (some use a built-in battery, others can draw power from a USB port)
• Connect your LG K120 to the reader's WiFi network, then use the reader's companion app (or a file manager that supports SMB/FTP) to browse, copy, or edit files on the microSD. No root, no system changes, no back cover removal.

Option 3: USB-to-WiFi Adapter (If You Already Have an OTG Reader) #

If you already own a regular OTG card reader, you can repurpose it with a USB WiFi adapter:

• Get a small, battery-powered or USB-powered WiFi adapter that supports "host mode" and is compatible with Android (look for models labeled "Android-compatible" or "OTG-ready")
• Plug your OTG card reader into the WiFi adapter, then plug the adapter into your phone's charging port
• Connect your phone to the adapter's WiFi network, then use a root-enabled file manager or a WiFi file explorer app to access the microSD. Note: Some adapters might require a small driver installation, but many modern ones are plug-and-play.

Quick Notes #

• For the build.prop edit: If your phone won't boot after the change, you can boot into recovery mode (hold power + volume down on most LG devices) and use the file manager in recovery to restore the backup build.prop.
• Wireless options are great for older phones with finicky hardware—they also let you access the SD card without keeping your phone plugged in, which is easier on the battery.

内容的提问来源于stack exchange，提问作者poupou