Hello!
Unlocking the bootloader of a smartphone typically requires a computer and some technical knowledge. However, there are a few methods you can try to unlock the bootloader without using a PC, although they may not be as reliable or widely supported as the traditional methods. Please note that these methods may void your warranty and could potentially brick your device, so proceed with caution.
For Realme C21Y:
1. Enable Developer Options: Go to Settings > About Phone > tap on the build number seven times to enable Developer Options.
2. Enable OEM Unlocking: In Developer Options, enable OEM unlocking.
3. Enable USB Debugging: Also in Developer Options, enable USB debugging.
4. Download and install the Realme Unlock Tool APK: You can find this APK file on the Realme website or various forums.
5. Open the Unlock Tool app and follow the instructions to unlock the bootloader.
For Vivo Y11:
1. Enable Developer Options: Go to Settings > About Phone > tap on the build number seven times to enable Developer Options.
2. Enable USB Debugging: In Developer Options, enable USB debugging.
3. Download and install the VUnlocker APK: You can find this APK file on various forums or websites.
4. Open the VUnlocker app and follow the instructions to unlock the bootloader.
Please note that these methods may or may not work for your specific device, as manufacturers often have different restrictions and requirements. It's always recommended to check official forums, XDA Developers, or other reliable sources for specific instructions related to your device model.
Again, proceed with caution as unlocking the bootloader can have risks and consequences. Make sure to backup your important data before attempting any modifications, and understand the potential risks involved.