Download and Install LineageOS 16 on Nexus 9 – flounder

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    Good news. You can now download and install LineageOS 16 for Nexus 9. Here is how to install LineageOS 16 on Nexus 9, with a step-by-step guide.

    Follow the links to get other LineageOS 16 and Android Pie ROM builds.

    This Nexus 9 LineageOS 16.0 build is brought to you by developer HashBang.


    If you like this ROM then do consider for a contribution to HashBang and LineageOS project:
    Donate to LineageOS project
    – No donation link found for HashBang


    Installing a custom ROM may require an unlock bootloader on Nexus 9, which may VOID your warranty and may delete all your data. Before proceeding further you may consider backup all data on the phone.
    You are the only person doing changes to your phone; neither the developer nor I can be held responsible for the mistakes done by you.


    Download LineageOS 16 for Nexus 9 - flounder

    Status of Nexus 9 LineageOS 16.0 – Android 9 Pie ROM:

    – Unknown


    – Unknown


    HOW TO DOWNLOAD AND INSTALL LineageOS 16.0 ON Nexus 9 – Android 9 Pie CUSTOM ROM:

    Following are the two sub-sections of this LineageOS 16 guide:

    1. First time installation of LineageOS 16 on Nexus 9
    2. Upgrading LineageOS 16 on Nexus 9 from a previous build of LineageOS 16 ROM
  • Follow this if you are flashing LineageOS 16 on Nexus 9 for the first time, or coming from another ROM:

    Points to NOTE:

    • Try to avoid restoring apps backup using Titanium Backup. It may break things up.
    • Don’t restore system data using Titanium Backup! It will definitely break the current installation.
    • It is also discouraged to Restoring Apps + Data using Titanium Backup.


    1. Download and Copy the LineageOS 16 Gapps and the Nexus 9 LineageOS 16 Android Pie ROM ZIP file to your phone.
    2. Boot into the TWRP custom Recovery to install this LineageOS 16.0 on Nexus 9.
      Make sure to have a Custom recovery like a TWRP recovery or any other custom recovery.
      – If not then download the TWRP recovery from Downloads link and follow the Custom Recovery Installation Guide (it’s a generic guide which will work for TWRP as well as any other recovery)
    3. Wipe the data partition (or do a factory reset), Cache partition, Dalvik Cache or ART cache and Format the System partition.
      – Here is a guide explaining how to wipe using TWRP recovery.

      This will delete all your data on your phone. You may consider complete backup of your phone data or take a NANDROID backup of the current ROM
      How to backup all data on your Android Device
      how to take NANDROID backup using TWRP recovery
    4. Install the Nexus 9 LineageOS 16 ROM file that you have copied into the phone.
      – Here is a post explaining how to install LineageOS
    5. Then install the Android Pie MindTheGapps for LineageOS 16 package.
      – Here is a post explaining how to install GApps using TWRP recovery.
    6. Reboot and Enjoy the Android 9 Pie LineageOS 16 on Nexus 9.

    Upgrading from earlier version of LineageOS 16 on Nexus 9 (flounder):

    1. Copy the latest ROM zip file of LineageOS 16 for Nexus 9, LineageOS 16 GApps and/or Magisk ROOT package to the phone
    2. Boot into Recovery.- Make sure you have a latest custom Recovery that should be able to flash the LineageOS 16 ROM update.
    3. Format or wipe the system partition from the custom recovery menu.
    4. Install the LineageOS 16.0 ROM for Nexus 9.
      – Here is a post explaining how to install LineageOS
    5. Reboot and see you have the GApps and ROOT access or NOT.
      – Gapps is built in such a way that it will sustain across ROM updates.
    6. If you don’t have GApps after upgrading the LineageOS 16 on Nexus 9, then flash the GApps.
      – Here is a post explaining how to flash GApps using TWRP recovery.
    7. If you don’t have ROOT after upgrading the LineageOS 16 on Nexus 9, then flash the SuperSU or Magisk or the Lineage SU binary.
      – Here is a post explaining How to Enable ROOT on LineageOS 16 ROM
    8. Once everything is done, reboot and Enjoy the LineageOS 16.0 on Nexus 9.

    Complete the initial setup and enjoy Android 9 Pie with LineageOS 16 on Nexus 9.

    After installing LineageOS 16 on Nexus 9 you may want to install Google Camera (GCam) or enable ROOT access on your phone and here is how you can do that:
    How to ROOT LineageOS 16
    GCam APK for Android Pie (this page contains a huge list of GCam for all available devices)

    If there is no ROOT access for some reason even after installing the LineageOS SU binary, then you can try SuperSU rooting guide to enable ROOT access.

    Stay tuned or Subscribe to the Nexus 9 (flounder) LineageOS forum For other Android Pie, Android Oreo ROMs, Nougat ROMs, or other ROMs and all other device specific topics.

    ? Google Camera APK | Mod APK

Timi Fadiran

It’s been a while since I tried to install a custom ROM on any device, so I probably should not have jumped back in right into Lineage 16 on my nexus 9, but I gave it a shot and I’m a bit stuck now

I flashed the ROM and on the first boot I got the “To start android, enter your password” screen. I saw people were saying type in “deafault_password” to get through this, but the system was freezing after a few seconds. The next solution I saw was to Format Data using TWRP.

Now when I boot, the system freezes as shown in the attached image.

Now when I return to TWRP I get a “Mount Decrypt Data” “Enter Password” screen. I’ve been hitting cancel and I have tried formating the data again in TWRP, but that doesn’t help.

I thought I might sideload a different custom OS, but ADB sideload also isn’t registering.

Any thoughts? Thanks.

Edit: I was able to go down to lineage os 15. Wanted to delete this post but can’t see that option. Thanks.



Just tried this ROM ( from flounder 15.1 ) and it reports ERROR 7 while installing.

Any tips?



It could just be a TWRP issue.
Can you tell me what is the TWRP version are you using and is it an OFFICIAL or unofficial TWRP build?

? Google Camera APK | Mod APK



Its TWRP 3.0.2-1 and I assume it is official, I just downloaded it from the TWRP list and was the latest at the time about a year ago. I have installed most Lineage 15.1 ROMs with it.

After wiping all but “Internal Storage”, I then proceed to install the ROM and get ERROR 7 within a few seconds.



After that there might be many changes, so it is always recommended to try with new TWRP.
I see the new TWRP for Nexus 9 is somewhat 3.2.3-0 or so.

? Google Camera APK | Mod APK


Now using flounder TWRP 3.2.3-0 and the ROM loaded and I rebooted.

After displaying the Lineage boot up sequence.. (3 circles)

I am presented with a screen saying “To start Android, enter your password”

and a keyboard, but then everything is locked up. I do not have a password !!!
(Have not loaded any GAPPs as yet)

Edit: After two ‘Factory Reset’s the keyboard was responsive for a few seconds, I managed to type in a random password, but then am told unsuccessful and need to do a factory reset and it all repeats. If I do not type anything in first second the keyboard locks up. The Nexus make a thumping sound once or twice just after boot up.

Timi Fadiran

The same thing happened to me. It would give me a few seconds to type then freeze. I saw people saying type in “deafault_password” to get through this, but the system was freezing after a few seconds.

The next solution I saw was to Format Data using TWRP. That got me past the password screen, but the device would freeze on the home screen shown in my original post. Also, at this point when I would return to recovery I would see a “Mount Decrypt Data” “Enter Password” screen. I would hit cancel and try formatting a few more times.

The next thing I tried was flashing the rom rebooting into recovery and then flashing gapps before the first boot. This seemed to stop the freezing, but then I got an a continuous error that pixel set up had crashed. At this point I gave up and installed Lineage 15.1 instead.


@ Timi
Thanks at least the problems are consistent, I saw your first post and hence tried the password but only got to ‘f’. Maybe we should wait for next tip from shibaa987.


Found this which gets rid of the password screen and Nexus fully boots up but is unresponsive to touch screen so is in effect locked up. Only Power off button works

Boot into Twrp and under Wipe you’ll find FORMAT DATA, not wipe data.. Format the data and the rom will boot . Note that you’ll lose everything from you phone, so it’s good to save files on pc before, if you have something important..

update — after further ‘hacking’ I now have a Nexus with only TWRP on it…… :-((((

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