Installing custom OS on original Nexus 7 (2012)
Before starting, make sure you have working adb (Android Development Bridge) tool on your PC. adb.exe is part of Android SDK, so if you have Android Studio, you should already have adb. If not, you can download Android Studio (or SDK only) from developer.android.com.
Warning: following instructions below will wipe all data on your tablet.
Step 1 - Unlock bootloader
- Enable USB Debugging on Nexus 7. Settings > Developer Options > USB Debbuging
Developers Options by default are disabled on all Android tablets. To enable them, got to Settings > About tablet and tap multiple times on Build Number
- Connect Nexus 7 to your PC with USB cable. When you get a prompt "Allow USB debugging" choose OK.
- Open command prompt and navigate to the location of adb.exe.
Exact path where the file is located depends on where you installed Android SDK. i.e. D:\sdk\platform-tools
- Run command adb reboot bootloader
Nexus 7 should reboot into FastBoot mode.
- Run command fastboot oem unlock. Accept a warring on the device.
- Nexus 7 should now have bootloader unlocked.