[One (M9) Q&A, Help & Troubleshooting] LaZiODROID:
SOLVED UPDATE: I did some more reading. I took the Bell (BM) rom zip

(named "0PJAIMG_HIMA_UL_L50_SENSE70_ATT_BM_1.32.666.6_R2_Radio_01.01_U11440221_59.04.50303G_2_F_release_426170_signed.zip"), and renamed it to "0PJAIMG.zip".

Copied that to the root of a microSD card and put that into the phone.

Booted phone with VOLDOWN+POWER and the flash process began. It rebooted a couple of times during the process. It said to hit POWER to finish. After that, phone booted normally (like out-of-the-box again).

With that said, I still would like to have root... so would still appreciate any input as to what I did wrong below. Thank you!

Hello. I'm afraid I have messed my phone up a bit, and would really appreciate it if someone could help me out.

It's a Bell HTC One M9 (0PJA110), and it is (was?) on 5.0.2 Lollipop. According to the RUU EXE I just tried (unsuccessfully), it says it is an image version (or HTC system version) 1.32.666.6.

Here's what I did, from out-of-the-box. I just wanted root access so I could use Titanium Backup, so I read a bunch of threads to get started. I thought I had gathered enough knowledge, so I:

1) Unlocked bootloader via htcdev

2) Flashed "htc-one-m9-lollipop-twrp-2.8.7.0-hima.img" to recovery. (I chose this version because I read in some threads that version 3 or higher of twrp doesn't work well if it is flashed to a Lollipop phone).

3) Rebooted, went immediately into recovery (so that TWRP could ensure it doesn't get overwritten)

4) Then rebooted again, and went into recovery (to make sure TWRP was still there)

5) At this point, I should have let the phone boot normally, to make sure that was OK. But I did not... so I cannot tell if this is where my trouble began

6) Next, in TWRP, I flashed "SR1-SuperSU-v2.79-SR1-20161221223537.zip". It seemed to go well.

7) Reboot from TWRP.

8) Phone shows first HTC logo, then goes to a black screen (black but illuminated). That's it.

My next thing to try was this Bell TWRP zip from a nice post on here. Filename is "Stock_Bell_LP_5.0.1_1.32.666.30_TWRP.zip". I tried to flash it via TWRP but it failed right away (I do not have the exact output but can try again to get the text, it if that helps).

Naturally I was starting to get worried, so I immediately started looking for RUU's so I could start over.

1) I re-locked bootloader

2) I tried a generic RUU ("RUU_HIMA_UL_M60_SENSE70_ATT_MR_NA_Gen_Unlock_3.35.617.31.exe") but it would not flash - I assume it is checking CID and knows it's not correct for my phone

3) I downloaded a Bell-specific zip from Androidruu ("0PJAIMG_HIMA_UL_L50_SENSE70_ATT_BM_1.32.666.6_R2_Radio_01.01_U11440221_59.04.50303G_2_F_release_426170_signed.zip", verified the MD5 matched whatever androidruu.com said it was.

4) Renamed the zip to rom.zip to make the next commands easier

5) Ran "fastboot oem rebootRUU", verified the RUU screen appeared, then "fastboot flash zip rom.zip"

It didn't work :( Here is the output:

target reported max download size of 800000000 bytes
Invalid sparse file format at header magi
sending sparse 'zip' (67085 KB)...
OKAY [ 4.791s]
writing 'zip'...
(bootloader) HOSD CL#493992
(bootloader) ERR [SD_UPDATE_ERR] update_fb_ZIP_buf: can not find ZIP hea
(bootloader) der
(bootloader) ERR [SD_UPDATE_ERR] sddownload failed: 22
(bootloader) ERR Update zip file failed.
(bootloader) ERR ZIP ERROR, exit read zip loop
(bootloader) ERR ZIP signature checking failed...
(bootloader) Update zip file OK
(bootloader) ERR ZIP ERROR CODE, 22
(bootloader) end@Done
FAILED (remote: 22: fail to flash via downloadzip)
finished. total time: 8.552s

I wish I could try a Bell RUU exe... but I am having a hell of a time finding one.

Any advice would be appreciated (regarding anything I did wrong up above, or regarding how I can get myself out of this mess). Thank you for reading.