Locking bootloader to use RUU to install Marshmallow

[AC Question]

So, I've unlocked and locked my bootloader to use an RUU before. I'm just lost as to what to do next. I have the adb command prompt up, and type in "fastboot oem lock" and it goes to <waiting for device> and just sits there. I close the command prompt, re-open it, type in "adb devices" and there are two extra emulators showing up with my device. Any and all commands don't work, stating "too many devices/emulators..." and something after that.

All I want to do is lock the bootloader and use the procedure on xda to get Marshmallow. I really don't want to have to send my phone to HTC and get charged $300 just to have it restored. If anyone can help, PLEASE DO. I'm done with the tinkering and playing around with SuperSU(also can't get that uninstalled, troublesome) and just want my phone to WORK.. and have Android 6 as well.

If anyone can please spoon feed me some help real-time, I can provide some social network contact info, or even my phone number, please. I need a helping hand here.

 

[Golfdriver97]

Welcome to the forums. Are you using ADB through Windows?

 

[isutke1287]

Yes. here is my progress to this point:

I started by factory resetting my phone (HTC One M8).
Then, brought the phone up to the bootloader screen, it is "modified (due to SuperSU)" and "unlocked."
Went to Fastboot and plugged my phone in to show Fastboot USB.
Shift-Right click in my C:\ADB folder and brought up the command prompt
The commands adb devices doesn't show my phone, but two emulators (I think those are port numbers?) that show "offline."
When my phone is up and running the device shows up when I put in "adb devices" so I do this:

adb shell
su
fastboot oem lock

and it just says <waiting for device> and does nothing.

Now, if I wait too long to get into the shell, I put in adb devices again, and it shows my device with the two emulators "offline."
I try to put in adb shell and it gives me the error that too many devices are present/running.. whatever it is.

Do I need to have the phone in fastboot usb to do it? My device doesn't show up in that mode.

 

[ctleng76]

If you place the device in Fastboot mode and then connect the USB cable, it should change to Fastboot USB mode. If that isn't happening, then your PC isn't detecting the phone. Make sure you have the latest USB drivers installed for your phone. Also make sure you are using a good USB cable. If you have a USB port that isn't USB 3.0 use it instead. Sometimes 3.0 causes problems. Also, if this is a desktop PC, make sure you aren't using one of the front USB ports. They can cause problems also.

Posted via the Android Central App

 

[Golfdriver97]

When using 'adb devices' and the phone is running in Android (up like you normally would have it) the adb script is correct. When in fastboot mode, you need to type in 'fastboot devices' that will show the device.

In order to lock the bootloader, you do need to be in fastboot mode.

 

[LeoRex]

" so I do this:

adb shell
su
fastboot oem lock

and it just says <waiting for device> and does nothing.
.

You phone is in fastboot mode, so adb commands won't see the phone... Hence the waiting message. Just run the fastboot command.