Always ensure you cross-reference your exact model variant code before flashing any custom kernels or partitions, as Sharp hardware remains sensitive to regional firmware mismatches.
While this policy appears universal, a detailed analysis reveals one possible (but narrow) exception: . It has been reported that only the SIM-free model of the Sharp Aquos Zero 2 might have had its bootloader unlockable at one point, possibly for beta testing purposes. However, even for this specific version, the possibility is now considered to be very low.
Input the universal unlocking command: fastboot flashing unlock (If your model uses older architecture, try: fastboot oem unlock )
Rooting gives you superuser access to the operating system. On a phone with a locked bootloader, this is nearly impossible. With an unlocked bootloader, it's straightforward.
Back in 2020, Sharp launched a beta program for Android 11 that also served as an official bootloader unlock tool for the SH-M13. While the official program page has likely been taken down, this is the roadmap you need to search for. Look for an APK called JoinDeveloperPreviewProgram.apk and a related ZIP file.
Type the following command and accept the prompt on your phone: adb reboot bootloader