The original title incorrectly mentioned the M9, this is actually the M7.. I've now updated this.
Going through some boxes the other day I found my old HTC One M9, which I had previously unlocked and flashed with various different ROMs.. Basically, this was the first device I ever actually tried any custom ROMs. That said, it's been so long, I don't have any of my old files left and I don't remember exactly what I did.
At this moment in time, the device is booting and running Xiaomi MIUI 8 (Android 6), but I'm unable to get into TWRP (constant bootloop) and I can't flash a new recovery image.
After a "fastboot reboot bootloader", I see the following details:
*** UNLOCKED *** M7_UL PVT SHIP S-OFF RH CID-11111111 HBOOT-1.54.000 RADIO-4T.36.3218.06 OpenDSP-v26.120.274.0202 OS- eMMC-boot 2048MB Apr 28 2015,09:16:24.0
When I try flash "twrp-3.3.1-1-hima.img", I get the following:
> fastboot flash recovery twrp-3.3.1-1-hima.img Sending 'recovery' (21852 KB) OKAY [ 2.072s] Writing 'recovery' FAILED (remote: 'image update error') fastboot: error: Command failed
I'm hoping to flash LineageOS from this thread, either 16.0 (as per the thread details) or the 17.1 or 18.1 available in the linked repository, but I can't do so until I get the recovery partition sorted out.
Please can someone help me fix whatever it was that I broke here..?