If your device is already rooted and has an unlocked bootloader (ironic, right?), you can lock/unlock using:

su
echo -n -e "\x01\x00\x00\x00" > /dev/block/bootdevice/byobootloader

Do not run this unless you know exactly what you’re doing. One wrong byte = hard brick.

Disclaimer: Unlocking a bootloader voids warranties on most devices, erases all user data, and can potentially brick your phone if done incorrectly. This article is for educational purposes. The author assumes no liability for any damage. Always check your device manufacturer’s official unlocking policy first.

Connect your phone to itself? No—Termux communicates internally using the Android Debug Bridge over TCP/IP (local). Run:

adb devices

You should see your device listed. If not, run:

adb kill-server
adb start-server
adb devices

A prompt will appear on your phone to allow USB debugging (even though it’s localhost). Accept it.

If you’re an Android enthusiast, you’ve probably heard the term bootloader unlock. It’s the gateway to custom ROMs, root access (Magisk), kernels, and full system control.

You might have also seen flashy YouTube thumbnails claiming: “Unlock Any Bootloader Using Termux – No PC Needed!”

But is that true? And more importantly, is it better?

Let’s separate fact from fiction and explore the safest, most effective way to use Termux in the bootloader unlocking process.

Termux operates in a sandboxed environment. To modify system partitions (which unlocking the bootloader entails), you must break out of this sandbox.

Unlike using Fastboot from a PC (which abstracts partition names), unlocking from within the OS requires specific knowledge of your device's partition layout.

There is a pervasive myth in the Android modding community that if you are "leet" enough, you can bypass OEM restrictions and unlock a bootloader directly from the device using Termux.

The short answer is: You cannot.

The longer answer requires an understanding of how Android's security architecture works. To understand why Termux fails here, you have to understand the hierarchy of trust on an Android device.

Before typing a single command, understand that unlocking the bootloader wipes ALL user data (photos, apps, accounts). Also, some manufacturers (like Samsung USA variants) lock bootloaders permanently. This guide works for most Xiaomi, OnePlus, Google Pixel, Motorola, and Realme devices.