Bootloop. No recovery. Bootloader locked.

Hello,

This afternoon, I was preparing to flash Oxygen OS 2.1 through twrp but I wanted to make a backup first. Attempting to load up twrp by holding Vol- and Power, my OPT flashed the starting frame of the boot animation for half a second before turning off. This repeated every 5 seconds. I could still boot OOS normally at this stage.

I decided to reflash twrp so as to make the backups, but on attempting to flash it, I saw that my bootloader was locked. So into fastboot mode I went, but trying to unlock it, it did the same as trying to get into recovery. As soon as I sent the command, "fastboot oem unlock", the screen went dark, flashed the starting frame for the boot animation, and promptly when dark again.

I now can't boot up normally, nor can I enter recovery. I can access fastboot mode, but I can't seem to make any changes.

I've attempted to use this solution as well as several other similar ones with no success.

I've had my OPT since 17th of August with absolutely no signs of trouble until this afternoon.

To me, it seems like it could be a hardware issue, but I'd hope it would last more than 40 days.

Any suggestions?

Thanks.