[Nexus 4 Q&A, Help & Troubleshooting] wammie:
Yes, the bootloader is the one where you press vol down and the power button together, that's the place where you select to go to the recovery, use fastboot.

First thing you got to do is turn on your phone on the bootloader as mentioned above. Then, assuming you downloaded this: [NEXUS 4 TOOLKIT V2.0.0] from here http://xdaforums.com/showthread.php?t=1995688, open up command prompt and go to this address with "cd C:\Google_Nexus_4_ToolKit" or where you decided to install your toolkit. On windows explorer, go there and rename fastboot-toolkit or whatever it is called to fastboot to make things simpler.

Type in cmd: fastboot devices to check if it recognizes your phone.

If it doesn't; then install these drivers (you should have your device already connected via USB to your computer): https://www.dropbox.com/s/a808emeelvxkwyc/usb_driver.rar

Go to Control Panel\Hardware and Sound > Device Manager. Your phone should appear with an exclamation mark somewhere, right click it and click on update driver:

-Click on browse my computer software

-Let me pick from a list of device drivers on my computer

-Have disk

-Browse for where you downloaded the drivers I linked you to then click ok.

-You should find within the next page something that says Android Bootloader Interface, double click it and finish the installation.

After that's done, then type in fastboot devices on cmd again, it should show up now.

Then, go to here and download TWRP 2.6.0.0 http://techerrata.com/file/twrp2/mako/openrecovery-twrp-2.6.0.0-mako.img , that will be your recovery. After you've downloaded move it to C:\Google_Nexus_4_ToolKit to make matters easier.

NOTE: IF YOUR BOOTLOADER IS LOCKED YOU WILL HAVE TO UNLOCK IT

, this can be done by typing fastboot oem unlock on command prompt

Now, simply type in this command: fastboot flash recovery openrecovery-twrp-2.6.0.0-mako.img you will now have a recovery on your device.

With the volume keys, choose to boot from the recovery. TWRP will load, while its loading, rename adb-toolkit to adb to make things easier. When its done loading, type in adb devices to see if it recognizes your phone, if it doesn't use your drivers again but this time instead of choosing Android Bootloader Interface, pick the one that says ADB.

When that's done, and it recognizes your device with the adb devices command you can now proceed to "push" or "copy/move a ROM you've downloaded in your computer towards your phone".

Of course you have to download a ROM, like Paranoid Android for example: http://goo.im/devs/paranoidandroid/roms/mako/pa_mako-3.69-20130722.zip , along with its GApps: http://goo.im/devs/paranoidandroid/roms/gapps/pa_gapps-full-4.2-20130719-signed.zip

You might have to even update your radio and bootloader in the future too, but let's leave it at that for now.

After you are done downloading the ROM of your choice, then type in these commands (assuming ADB works)

adb push pa_mako-3.69-20130722.zip /sdcard/

adb push pa_gapps-full-4.2-20130719-signed.zip /sdcard/

Having moved these two files inside your phone, now its time to flash them.

1) Go to Wipe on TWRP and simply swipe to factory reset

2) Go back and click on Install, look for pa_mako-3.69-20130722.zip and then add pa_gapps-full-4.2-20130719-signed.zip to the queue, swipe to install.

After that's done, simply reboot your phone and it should start booting up Paranoid Android and you're done. Might give you a few issues if you have an old radio and bootloader, but that can be fixed by flashing the new versions of these two in TWRP. Can be found here: https://www.copy.com/s/JniBu/4.3 files (mako) (these can be pushed via ADB like before, or you can simply download them on your phone when its working)

Hope this helps, don't think I can be more detailed.