[One (M8) Q&A, Help & Troubleshooting] redpoint73:
Forgive me while I rant, but I see this all too often (wiping partitions when you don't know what they are). Quite frankly, if you don't know what you are wiping, or what the result will be, then don't wipe it. It doesn't take much research to find out what each wipe option (partition) is. There are far too many post on here to the effect "I wiped system and now I have no OS". Well, seeing as system and OS are the same thing, that is an obvious outcome. Plus, these options are called "Advanced" for a reason. If you don't have advanced knowledge (or at least research what the options mean), don't mess with them.

Further, wiping

everything

in TWRP Advanced Wipe options means you wiped your internal storage and removable SD (if you have one), both of which are the possible locations for TWRP backups (internal storage is the default backup location). So again, since you wiped

everything

, of course you wiped your TWRP backups.

First of all, that is not a valid OS number for the M8, and the likely reason is that you typed it incorrectly. You really need to post specifically and correctly, otherwise we can't know what you are doing. It might seem unimportant or nitpicky to you, but tiny differences in these numbers can have big implications, so you really need to try harder to get it right.

Your description is still far to vague to mean anything. "a boot.img from some YouTube" Do you seriously think that is going to help us help you at all? There are thousands (if not millions) of videos on YouTube. We can't have any idea what that means. You really do need to give the exact steps you've tried and the exact files, if you want proper help.

While you can't use the link function to post links, if needed you can post the text. If the forum still won't allow it, just obfuscate the URL with "dotcom" at the end or something similar.

Syntax is just the

exact

command as you typed it (order of the typed words, spelling, etc.). This is extremely important, as a single typo such as a wrong character, improper order, etc. will cause the command to fail.

For instance (and I'm not sure if what you posted above is the exact syntax you actually used or not) for the above command, there is no such thing as "Flashboot", it should be fastboot. And fastboot/adb commands typically don't have the command words capitalized like you have it. Exception is if a directory or filename has caps, in which case it needs to match

exactly

.

My apologies there. Pesky pronouns! Of course, on the internet, unless we know beforehand, we can only guess at the proper pronoun; as it often gets impractical to type "he/she" or non-gender specific "they". I'll try to get it right in this thread, moving forward.

Just cut and paste the getvar data. In Windows command prompt, you can right mouse click, select "mark" to highlight the desired getvar text; then Ctrl-C to copy (then just right click Paste or Ctrl-V to paste into an XDA forum message).

---------- Post added at 10:22 AM ---------- Previous post was at 10:15 AM ----------

USB debugging only affects adb use while the phone is running. It doesn't affect fastboot, and fastboot will work even when no OS. Further, RUU only requires fastboot, and even then only to reboot into RUU mode.

---------- Post added at 10:24 AM ---------- Previous post was at 10:22 AM ----------

If you don't understand what it is, you shouldn't be flashing it. You haven't sufficiently described what it is (or linked the location) so we can't possibly know what it is, or properly help with it, either.

Honestly, no offense intended, it seems like your understanding and knowledge of what you are doing is pretty shaky. I'd suggest reading up for an hour or so of the basic tutorials, guides, Index threads, etc. before doing anything more with the phone (aside from RUU, which is what I am about to recommend for you).

---------- Post added at 10:32 AM ---------- Previous post was at 10:24 AM ----------

This is

completely false

.

You only need s-off to flash hboot, radio, change CID/MID, and a few other things. You can flash M8 ROMs, kernels, and a good number of other things from TWRP with s-on. Just find the proper desire ROM, and put it on removable SD or adb push to internal storage; then boot into TWRP and flash the ROM to get OS back.

But RUU is the best option for you.

Absolutely.

You will need to relock the bootloader with the command: fastboot oem lock

After that, verify in bootloader that it says RELOCKED near the top of the screen.

Then just run the following RUU to get the phone running, and also updated to AT&T Lollipop: http://dl3.htc.com/application/RUU_M8_UL_L50_SENSE60_ATT_MR_Cingular_US_4.28.502.1_Radio_4.0.U605611@50319A_40.45.C33065.00_F_release_426617_signed_2.exe