Originally Posted by simbin
Only want Super Mario Run on my Android 4.4 (Chinese custom rom) phone. Locked bootloader so can't upgrade rom for Magisk. Why does Nintendo insist on being D about it?
I had the same problem on a Blu Life One X3... one is supposedly able to unlock the bootloader, but the VolUp button doesn't work in FastBoot, and that's what's needed to confirm unlocking the bootloader!
So I used a trick
... I flashed TWRP using SP Flash Tools... I set up SP Flash Tools with the necessary files and clicked the button to start it flashing the files WITH THE PHONE RUNNING NORMALLY. Then I shut down the phone... apparently it drops all security for just long enough that I was able to push TWRP in as the new bootloader.
Give it a try, it might work for you. Remember to enable Developer Options, and inside that enable OEM unlocking and USB Debugging.