@sagar.pradhan Please post a link or two to those.

But seemingly they are all fixed: (-edit: opps. reading further I see there are many not fixed. Sorry about that. )

https://bugs.launchpad.net/ubports-android/+bugs

@tom
" I flashed ubuntu over the baseband of cm12.1. I thought that was what the advice was! "
Yes, I think that was the advice.

My cheap advice about mixing systems -> " dual booting is just not worth the trouble."

I changed the status of my attempt to stopped.
I don't have any interest in in-depth learning about node.js or javascript so best for me to quietly bow out of this bounty.
Someone with the skill set already might find is a trivial bounty to fix.

The purpose of this topic is to document the Recovery image details of the FP2 as I initially received it.

<icon>
horizontal android, chest door open, exposing red triangle with exclamation point.

Android system recovery <3e>
r4275.1_FP2_gms69_1.9.3
 
Volume up/down to move highlight;
enter button to select.

reboot system now
apply update from ADB
wipe data/factory reset
wipe cache partition
reboot to bootloader
power down
view recovery logs
apply update from sdcard

Plugged USB cable results in dmesg:

[65653.044636] usb 3-1: new high-speed USB device number 25 using xhci_hcd
[65653.173731] usb 3-1: New USB device found, idVendor=2ae5, idProduct=9039
[65653.173738] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[65653.173741] usb 3-1: Product: Android
[65653.173744] usb 3-1: Manufacturer: Android
[65653.173747] usb 3-1: SerialNumber: f8c9f680
[65663.005036] usb 3-1: USB disconnect, device number 25
[68831.732542] perf interrupt took too long (2509 > 2500), lowering kernel.perf_event_max_sample_rate to 50000

Scrolling down and selecting option "apply update from ADB"
FP2 responds with same icon.
Text bottom of screen:

Now send package you want to apply
to the device with "adb sideload <file name>"

resulting dmesg:

[69031.019059] usb 3-1: new high-speed USB device number 26 using xhci_hcd
[69031.148680] usb 3-1: New USB device found, idVendor=18d1, idProduct=d001
[69031.148687] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[69031.148690] usb 3-1: Product: FP2
[69031.148693] usb 3-1: Manufacturer: Fairphone
[69031.148696] usb 3-1: SerialNumber: f8c9f680

Oppsie : ) Waited too long.

Now send package you want to apply
to the device with "adb sideload <file name>"...

Timed out waiting for package.

Installation aborted.

Reselecting option "apply update from ADB"

adb devices reports.

List of devices attached 
f8c9f680        sideload

This is just a heads up on getting adb access while running the stock android version.

Do the usual ->settings->about phone
Then tap Build Number till it tells you are a developer.
Then go back:
Now select [] Developer options
Turn on debugging.

Now connect USB cable and "USB computer connections" should then be available to make selections.

Actually if you want adb shell to work you must unselect all options.

Then a pop-up asking if you want to authorize such and such computer access, Say yes.

And adb shell should work.

Hm I would suggest that what you have asked for is available on GitHub but perhaps start with wiki.ubports.com.

Reading rootstock script and modifying it to your needs is good way to learn this process. I have also been doing this.

Are you able to flash and use the boot and recovery partitions?

Great you are trying Ubports out.
So it sounds like AppArmor permission problems. Hmm, but other apps are working?

What did you flash your N5 with?

I'll attempt to tell you how to find the ones built by the Ubports Jenkens server.
If you execute this

ubuntu-device-flash -v --server=http://system-image.ubports.com touch --channel=ubuntu-touch/devel_rc-proposed –device=hammerhead --download-only

Then look in

~/.cache/ubuntuimages/pool  

You will find among other files, this one

59147132 Dec 21 18:57 device-1343cffe4d2fe5b529e198a4182e1b20de176d284b1d340f5b44f3ac25896e79.tar.xz

If you then extract you will find two directories labeled partition with boot.img and recovery.img within and another directory labeled system.

Hopefully you were able to buy a N5 at a good price : )

I'd recommend you flash to devel_rc-proposed
and set updates to manually only.

Perhaps you might offer up a bounty? I think they are setup to work with Bitcoin (฿).
@below-freezing might be able to offer guidance. example

I changed the status of my attempt to stopped.
I don't have any interest in in-depth learning about node.js or javascript so best for me to quietly bow out of this bounty.
Someone with the skill set already might find is a trivial bounty to fix.

Of the Ubports channels for N5 devel_rc-proposed is definitely the better choice at this point in time.

OK. Stable channel is rather old at this point. I've had the best results with using current devel_rc-proposed but with rootfs of 7/28/2016. It's not straight forward how to do that though. I think very soon we will have better options available.

You are definitely looking in the right place for answers. Have look at this page for an understanding what is happening:
https://wiki.ubuntu.com/Touch/ContainerArchitecture

Grab boot.img , recovery.img, and system.img from

https://seafile.nigle.nl/d/62d505f0a7/

Grab rootfs (ubuntu-xxxx.tar.xz) and device-xxxx.tar.xz from http://system-image.ubports.com with:

ubuntu-device-flash -v --server=http://system-image.ubports.com  touch --channel=ubuntu-touch/devel_rc-proposed –device=FP2 --download-only

Modify a copy of rootstock-device-install to use the parts of device-xxxx.tax.zx we need.
rename to rootstock-FP2-install

Boot to fastboot mode with by pressing volume down and power button till Fairphone logo comes up. Connect to USB cable
Check for fastboot mode.

sudo fastboot devices

sudo fastboot flash boot boot.img
sudo fastboot reboot-bootloader
sudo fastboot flash recovery recovery.img

Manually boot into recovery with up-volume button and power button.

use modified rootstock-FP2-install to install rootfs, system.img, and custom.tar.zx

Boot phone to Ubuntu Touch.
Set security.
Unset auto updates.
Verify adb
Set up /home/phablet/.ssh
run

phablet-config writable-image

To make rootfs writable.

adb shell

sudo add-apt-repository ppa:peat-new/fp2-custom-test
sudo apt-get update
sudo apt-get upgrade
sudo install xterm xauth mir-android-diagnostics mir-test-tools mir-demos synaptic

Test mir, etc.

I'll attempt to tell you how to find the ones built by the Ubports Jenkens server.
If you execute this

ubuntu-device-flash -v --server=http://system-image.ubports.com touch --channel=ubuntu-touch/devel_rc-proposed –device=hammerhead --download-only

Then look in

~/.cache/ubuntuimages/pool  

You will find among other files, this one

59147132 Dec 21 18:57 device-1343cffe4d2fe5b529e198a4182e1b20de176d284b1d340f5b44f3ac25896e79.tar.xz

If you then extract you will find two directories labeled partition with boot.img and recovery.img within and another directory labeled system.

Great you are trying Ubports out.
So it sounds like AppArmor permission problems. Hmm, but other apps are working?

What did you flash your N5 with?

Just as I was about to make a back up copy of FP2 stock android it wants to upgrade to a newer version. Since I had already let it upgrade once before, I thought, why not? So now I'm waiting for the apps to be upgraded.
Build number now is r4275.1_FP2_gms70_70_1.10.1
I'm not planning to test new update today. I'm take a quick look to see if boot and recovery have changed any.