Can't access bootloader
There is no "then press POWER and VOL DOWN" in the instruction, after release both power & volume up, press only volume down button.
I was very frustrated by the directions I got from HTC inserted below:
press Volume Down and while pressing Volume Down, press Power holding both buttons to start the device into Bootloader mode (now Download mode for One M9 and newer devices). If you have difficulty, power up normally, go to Settings->Battery and deselect Fast boot. Power down and try again.
Then I came here after a Google search listed many hits, this one seemed like the best (as always XDA would be my first choice) of them all. Then I tried the button instructions here. But all led to further frustrations. I am an antiquated fossil of 63 years old, a mere high school graduate of the Class of 1971, a once upon a time in dog years (1996-1998), Novell NetWare CNA/CNE network geek, PC/server hardware tech, systems programmer, systems analyst, and Windows OS & Office Suite Desktop End-User Support Specialist. In other words, I am qualified to not only read English, I can even compose my thoughts and present them using it.
Most of the time.
What device is that ? Definitely not M8 & not M8 dual SIM.
Great question!! Unfortunately, the answer may be the solution to at least most of the problem. The next question would be "What implications does that present? Does that make it irreparable and essentially worthless?"
The serial number is EXACTLY what you posted;
123456789ABCDEF
Just to be thorough, here are the other details. But, I did NOT get these using ADB, because I can NOT get ADB to work at all. These details came from About Phone.
IMEI Slot1: 355131214676268
(I forgot the label): 78
IMEI Slot2: 355131214676276
(?????????? label): 78
S/N: 123456789ABCDEF
Model: M8
Android version: 4.4.2
Baseband:
MOLY.WR8.W1315.MD.WG.MP.V43, 2014/09/17 10:10
Kernel: 3.4.67 root@zy-12 #1 Thu Sep 24 09:46:01 CST 2015
Build Number: X5_72KK_KK_3GW_B15_EMMC_32_4_QHD_XLD_MII_ZX 20150924.103623
Custom Build Version: 1442306041
If you still can boot, enable usb debugging in Developer options then run adb devices to see the serial no.
If it come out as weird as 123456789abcdef then it's fake htc.
Needless to say, but I already told how I got this. I don't mean to sound like a smartass, but I can't help it. I flashed and modded my first Motorola Droid back in 2012. This ain't my first rodeo, its' just that this phone has been one of the more frustrating broncs I've tried to break lately. If this is a "FAKE" HTC phone, I would not be surprised to learn that. I had not been aware until now that there are fakes.
I mean, WTF?
Your screenshot looks familiar and I manage to find the same that written in English
https://xdaforums.com/showpost.php?p=50678371&postcount=3
Yep. Now, what do you recommend? WAIT!
I want you to know that I followed the link to your GUIDE. Very Well done, sir.
I found it remarkably well organized, detail specificity very professionally presented, and written for a layperson without sacrificing the value of educating them with vernacular of the high level technician. I commend you.
With that said, whether ir is while I have the OS up, or from recovery menu ADB function, this is what I get when trying to use ADB on this potentially worthless waste of time:
C:\Program Files (x86)\Minimal ADB and Fastboot>adb start-server
adb server version (31) doesn't match this client (35); killing...
error: protocol fault (couldn't read status): Connection reset by peer
error: could not install *smartsocket* listener: cannot bind to 127.0.0.1:5037: Only one usage of each socket address (protocol/network address/port) is normally permitted. (10048)
could not read ok from ADB Server
* failed to start daemon *
error: cannot connect to daemon
AND
C:\Program Files (x86)\Minimal ADB and Fastboot>flashing get_unlock_ability
adb server version (31) doesn't match this client (35); killing...
* daemon started successfully *
error: no devices/emulators found
So, with all that, what say you to my question, "Now what?"
My Opinion, if it is a fake, disassemble it to explore the guts,
like a 1st year med-student exploring human anatomy on a
homeless, unidentified cadaver from the Morgue.