[Nexus 5 General] ThatGuy94:
This is a guide of how to dualboot KitKat and Android Lollipop on a Nexus 5. This will allow you to test out Lollipop while keeping a stable ROM to run as a daily driver. I am running CM11, but you can do this with any KitKat ROM, even stock.​

REQUIREMENTS

Nexus 5

Root

Unlocked bootloader

MultiROM

A brain

At least 1 GB of free space (I recommend 4 GB though)

1. Setting up.

I'm assuming you are already rooted if you are planning on doing this. If not, follow this guide to root and unlock the bootloader. http://xdaforums.com/google-nexus-5/orig-development/nexus-5-cf-auto-root-t2507211

1. After verifying you have root on your phone, download MultiROM Manager off Google Play: https://play.google.com/store/apps/details?id=com.tassadar.multirommgr&hl=en

2. Install and open MultiROM Manager and install MultiROM, Recovery and the patched kernel.

Here is what the following is...

MultiROM: This boots before the system and gives you the option of what system you want to boot. When you select the system, it then hands it off to boot. This will not overwrite your current ROM, but make a backup to be safe

Recovery: This is a custom TWRP recovery with options to install a secondary system

Kernel: This will patch your kernel with kexec-hardboot patch which is requires to dualboot in general.

2. Installing Android Lollipop

1. After you install and verify that MultiROM is installed on your phone, download the Android 5.0 flashable zip from the downloads section at the bottom

2. Reboot into the recovery and go to Advanced> MultiROM> Add ROM

3. When you get there, set ROM type to Android and select "Dont share" for kernel sharing and then press next

4. select ZIP file and install "N5_L_PREV_LPX13D.zip" you downloaded earlier and flash it.

If you wish to not root L, you can go ahead and reboot your phone into Lollipop (The first boot will take several minutes). If you do want to root, go on to the next step. Your primary ROM won't be touched as your primary ROM and its root status won't be affected when using MultiROM.

3. Rooting Android Lollipop (optional)

Rooting is completely optional and is not required for it to run. You need to install root if you do plan on using root apps or busybox on Android 5.0.

As of the LPX13D build, there have been changes made in the bootloader that will prevent SuperSU or root from working. If you want to root on the LPX13D build, you will need to flash this bootloader: http://www.reddit.com/r/Nexus5/comments/2jkx7a/

1. Download the SuperSU zip in the downloads section and save it to your phone.

2. Boot into recovery and go to Advanced> MultiROM> List ROMs and select the L ROM you installed earlier (unless you renamed the zip file or the system name, it should show"N5_L_PREV_LPX13D")

3. Select flash zip and flash the SuperSU zip you downloaded.

4. Reboot and you should now be rooted.

Updating Android Lollipop

As of right now, there are issues if you try to do a dirty flash from DP1 to DP2 (These are issues with Android L and not MultiROM). These issues include home button not working, quick settings pulldown not working, no lockscreen when there is one and data issues (at least with Sprint). If you are coming from LPV79 and updating to LPV81C or LPX13D, it is recommended to do a clean install to avoid these issues. If you are doing a fresh install, you don't have to worry about this issue

Android Lollipop Bugs

These are issues with Android Lollipop and not MultiROM

-The issues stated above when certain things don't work after a dirty flash

-During the inatial setup, the phone may freeze and require reboot when trying to connect to wifi (seems like a new bug with LPV81C). The phone will say Connecting and show a white box before it freezes

-Some apps will crash or be buggy (this is to be expected though with the transition to ART)

-More bug reports can be found [Here]

-A list of apps that have issues with working with Android L can be found [Here]

Downloads

Android Lollipop flashable zip: http://xdaforums.com/showpost.php?p=56112246&postcount=5498

L Root: http://download.chainfire.eu/578/SuperSU/UPDATE-SuperSU-v2.14.zip

Thanks

Chainfire for CF Autoroot and SuperSU

Tasssadar for MultiROM to make this dualboot possible

davy917 for posting a solution for people having internal storage issues with L

For more information and general use of how MultiROM works, go to its main thread [here]

Also if you do have the issue where your internal storage doesn't mount, follow this solution found [here]