Bootloader unlocking is the first step in your journey to root Android devices or flash custom ROMs / Generic System Images (GSIs). Unfortunately, the bootloader unlock process isn’t a one-size-fits-all affair as many online tutorials portray; your approach varies with the device.
What is bootloader unlocking and why unlock the bootloader?
Your Android device ideally ships with a locked bootloader (except on some old models). This ensures that only factory-signed or official firmware will boot on the device. Flashing a modified file on a locked bootloader would brick the device. ‘Bricking’ refers to a situation where an Android device is unable to boot to the home screen.
Unlocking the bootloader is the process of disabling this check or restriction. This allows you to flash modified files like TWRP to the recovery partition, a magisk-patched boot image to the boot partition, GSIs or custom ROMs to the system / super partition, etc without bricking the device.
What are the requirements to unlock the bootloader on an Android device?
There’s a very good chance that you will lose data because the bootloader unlock process mostly requires you to do a factory reset. Since a factory reset wipes your data, backing up your important stuff should be the first thing you do. There are other bootloader unlock techniques that do not result in data loss but they don’t apply to all devices.
There are no other strict requirements per se aside from your device being supported for unlocking; whether officially or via exploits. You of course need to have charged it to an extent depending on the unlock method you’ll be using.
Are there any disadvantages of unlocking the bootloader or risks of having an unlocked bootloader?
First off, you might run into problems with some apps – like bank apps – which won’t work once root or an unlocked bootloader is detected. You shouldn’t have this problem with Over The Air (OTA) updates.
The risk associated with an unlocked bootloader stems from being able to modify the partitions i.e flash unsigned or altered files. This means a malicious script can inject malware into your device. This doesn’t necessarily mean a locked bootloader guarantees complete security but it’s a layer of protection.
Can I relock the bootloader?
Yes, you can. The procedure should be similar to the bootloader unlock technique. One common oversight is relocking the bootloader while running on altered partitions. This will automatically brick your device.
You should always flash the full factory or official firmware to your device before relocking the bootloader
Bootloader Unlocking Techniques For Android devices
Now to the exciting part where we discuss bootloader unlock tools and practical techniques for various Android devices. Most of the guides you’ll come across online only consider one technique/approach; the good old OEM unlock then fastboot OEM unlock technique, and they stop right there. It would’ve been great if that worked most of the time wouldn’t it?
The bootloader unlock command or method you employ depends on two things:
- Brand e.g. Samsung, Huawei, Xiaomi, Motorola, HTC, etc.
- Chipset e.g. Mediatek, Qualcomm, Spreadtrum / Unisoc, etc.
Let’s get started.
Unlocking The Bootloader Using Fastboot And OEM Unlocking
This is the most popular method because it is generic. Using this step involves:
- Setting up fastboot on your PC
- Enabling USB debugging on the device and then enabling OEM unlock.
We’ve created a guide on how to unlock the bootloader of an Android device using fastboot so check it out for details.
The downside is that it doesn’t work on every device. If you’re looking to unlock the bootloader without enabling OEM unlock then this method isn’t for you
Unlocking The Bootloader On Mediatek Using MTK Client
MTK Client is a free tool that enables you to unlock the bootloader on Mediatek devices in BROM Mode. This tool is for Mediatek devices only. If you’re not certain of your device’s chipset then see our tutorial on finding out your device’s chipset.
This tool requires you to:
- Setup Python on your PC
- Install USBDK drivers
- Know how to boot your Mediatek device into BROM mode
- Setup the MTK client tool
See our detailed guide on using MTK Client to unlock Mediatek bootloader. This tool is great because you have a good shot at unlocking the bootloader where there’s no official support for your device; unfortunately, it doesn’t work for every Mediatek device.
Unlocking The Bootloader On Spreadtrum Or Unisoc
Unlocking the bootloader on Spreadtrum / Unisoc devices using the fastboot and OEM unlock method used to work just fine until Android 9 (Pie). You now require a bootloader identifier token or bootloader unlock signature.bin to successfully unlock the bootloader.
A PC running Linux (we used Ubuntu) gives you a better shot than using a Windows PC. You can run Ubuntu on a Windows PC with Linux Live USB.
Follow our guide on how to unlock the bootloader of Unisoc or Spreadtrum devices for details on this technique. This is a very useful technique but it only works for brands that used Android’s default primary keys for signing.
Unlocking The Bootloader On Qualcomm Devices Using QFIl And Leaked Engineering Bootloader File
The ABL partition is the site of the bootloader state on some Qualcomm devices. If there’s a leaked engineering bootloader file for your model then simply flashing it to the ABL partition using QFIL will unlock the bootloader. The LG V50 is one of a number of models whose bootloader can be unlocked using this method.
Unlocking The Bootloader On Samsung devices
Bootloader unlocking on Samsung devices requires you to first enable OEM Unlock. If this option is missing then ensure you’re connected to WiFi. If it’s still missing then there are other tricks like waiting or back-dating. The next step (after enabling OEM unlock) depends on the Samsung model.
Enabling OEM unlock will trigger bootloader unlock on old Samsung models while new models require an extra step. Follow our Samsung bootloader unlock guide for detailed steps.
Some Samsung models either don’t present the OEM unlock option under USB Debugging or don’t provide the bootloader unlock option in Download mode. You’ll be unable to unlock the bootloader of such models.
Unlocking The Bootloader On Xiaomi Devices
Bootloader unlock on Xiaomi devices requires a bootloader unlock tool called Mi Unlock Tool. This tool requires USB debugging and OEM unlock enabled on the device then linking the device to a Mi Account. It’s important to have a SIM card with mobile data turned on as your source of internet on the device.
Our Xiaomi Bootloader unlocking guide contains all the necessary steps and tools you’ll need. One downside to this method is that although it’s the official bootloader unlocking method, it has a significant waiting period.
Unlocking The Bootloader On Motorola Devices
Bootloader unlock on Motorola devices requires a bootloader unlock code. To obtain this code, you need:
- A Motorola account
- An unlock token obtained from the device
Armed with both, you head to the Motorola bootloader unlock code request page where you’ll choose your model from the list of supported models and then provide your unlock token. The unlock code will be emailed to you once generated. You can follow our Motorola Bootloader unlock tutorial for detailed steps.
Although this is the official Motorola Bootloader unlocking technique, relatively few models are supported.
Unlocking The Bootloader On HTC Devices
Bootloader unlock on HTC devices requires an unlock binary file (.bin). To obtain this file, you visit the HTC dev page, create an account then follow the wizard. You’ll need to connect your device during the process after which the unlock_code.bin file will be emailed to you. Our HTC Bootloader unlocking guide contains the procedure step-by-step.
Just like other official bootloader unlocking methods, not all models may be supported.
Unlocking The Bootloader On LG Devices
LG no longer provides official bootloader unlocking support so consider the Mediatek or Qualcomm methods mentioned above. You should also know that they’re shutting down their smartphone business.
Unlocking The Bootloader On Huawei Devices
Huawei -like LG- no longer provides official support for bootloader unlocking so try the same approach as LG or lookup paid Huawei bootloader unlocking solutions.
The above collection has covered bootloader unlocking for most Android devices. If your model, brand, or chipset isn’t covered on the list then drop it in the comments section and we’ll be happy to look into it.