VoLTE Implementation For Google Pixel 3a/3a XL

atarilinux

I have some more info on the error message and the super partition.

On the cannot stat error:
https://stackoverflow.com/questions/34254164/getting-an-error-cp-cannot-stat-when-trying-to-copy-files-from-one-folder-to-an

Postmarket OS has some info on the super partition and dynamic partitions:
https://wiki.postmarketos.org/wiki/Android_dynamic_partitions

From the Android documentation:
https://source.android.com/docs/core/ota/dynamic_partitions/implement

Now we just have to see how we can put this all together for Ubuntu Touch.

atarilinux

I found something else that may be similar on the forums. It is regarding Fairphone 4 though...but there is a partition issue. There may be something we can glean from here.

https://forums.ubports.com/topic/11173/fp4-can-install-android-11-12-13-and-e-os-11-12-13-and-postmarkos-except-ubuntu-touch

atarilinux

Furthermore, Lineage OS has a recent build that should incorporate the retro-fitted super partition changes for the Google Pixel 3a. See below the github page.

https://github.com/orgs/LineageOS/repositories?q=android_device_&type=all&language=&sort=

ikoz

@atarilinux All modern UT devices already work with the super partition. I don't understand what you mean by "implementing" it, the only thing UT has to do is mount them, which is already done.

atarilinux

@ikoz

@fredldotme mentioned having an issue with the retro-fitted super partition for the Google Pixel 3a build on a QA call. He stated that we will need to figure that part out to get it working. When the Google Pixel 3a Android 12-based Ubuntu Touch port was trying to be built, we get the following error messages below, which refernces the partitions. If this has already been worked out on other Ubuntu Touch ports can the fix be applied to this one, or is this a different issue entirely? Any insight is recommended! Thanks!

cp: cannot stat 'partitions/': No such file or directory
System image: Applying update: halium_halium_arm64.tar.xz
cp: cannot stat 'partitions/': No such file or directory
System image: Applying update: device_sargo.tar.xz
System image: Applying update: version.tar.xz
cp: cannot stat 'partitions/*': No such file or directory
losetup: /dev/loop0: detach failed: No such device or address

ikoz

@atarilinux The cp error is normal and happens on all builds, the actual problem is the last one. From my understanding based on an older discussion in the porting telegram group, the retrofitted partition is used for older devices which didn't have the new super partition. However, it shouldn't be impossible to get it working, as others got their device booting, mounting the android partitions is necessary only for getting the android container running.

Anyways, more experienced people are active on the telegram group, so you may want to ask them.

atarilinux

@ikoz

Yes, that is correct. The retro-fitted partition is what the Google Pixel 3a uses. Thanks for helping with reading the error! I'll see what I can find out on this. If you know of anyone who may have some insight, can you let them know this is something we are looking to get resolved?

As we understand it, VoLTE works with a more recent version of Android. We are hoping to make this possible for the Google Pixel 3a on Ubuntu Touch as well. It has been confirmed that other alternative OS's already have VoLTE implemented for the Google Pixel 3a, so I think we have some resources we can potentially pull from if we need to. I'm not entirely sure what is being discussed on Telegram or if people may already be looking this.

mr_growl

@atarilinux No prob. So you know, I've just ordered a Pixel 3a XL for playing around on so if you'd like any specific versions of lineage tested for VoLTE, let me know. I gather that testing with a version based on 12.1 is the one you're most interested in?

atarilinux

@mr_growl

Thanks so much! Yes, that is correct! We are currently looking at Android 12.1 for two reasons:

The unfinished Ubuntu Touch port is based around this version.
This version is supposed to have the VoLTE patch included.

The current struggle seems to be with the retro-fitted super partition, but it seems like this has already been worked out with other Ubuntu Touch ports. If we can get whatever worked for them applied to this port, we may be able to get this working if I understand the recent comments correctly. We may have other issues down the line, but that looks like the first thing we need to address.

atarilinux

Just an added note on trying to troubleshoot the loop error:

Error:
losetup: /dev/loop0: detach failed: No such device or address

Note:
"Loop devices are provided by a kernel module. Therefore, you need special privileges to access them. You also need them to be exposed into your container, or you need to manually create the device files."

I'm not sure if something may have changed between Android 9 and Android 12.1 for this. We would need to investigate this error in addition to the retro-fitted super partition issue.

Eric H

@atarilinux
I see same errors (cp and losesetup) in other ports.
For example:

here's an example of flashing devel images on a device with a super partition :
https://gitlab.com/EricHeintzmann/ubuntu-touch/xiaomi-surya/-/wikis/fastboot-flash

About fastbootd :
https://source.android.com/docs/core/architecture/bootloader/fastbootd

atarilinux

@Eric-H

Thanks! I do see these same errors from the logs of the other device ports you sent me...so maybe that isn't the problem mentioned in the QA call? Also, thanks for the fastbootd link!

Quick question... for any of these devices you sent, are we looking at a retro-fitted partition? The reason why I ask is that I'm trying to match some of this up to the issue presented on the QA call. That way we can see if this part can be resolved.

Eric H

@atarilinux
AFAIK, these devices use a super partition, but not a retro-fitted one.
But, I don't think the build system is aware of the partition type.

atarilinux

@Eric-H

Unfortunately, the Google Pixel 3a uses a retro-fitted partition for Android 12.1 and not the common super partition used in newer Android devices. According to the QA call:

Issues with building/installing:
*Issue with getting image on phone
*Has retrofitted system super-partition, this means two partitions act as they are one
*Has not been installed in this type of environment, we would need to figure it out

Also, the build was not completed.

It very well possible that this was figured out with these other device ports. However, these issues would need to be worked out with this Google Pixel 3a build as I understand it. I'm assuming that is why this build is not considered complete.

Eric H

@atarilinux

You have a retro-fitted super partition
You have images
You have the procedure to flash images in retro-fitted super partition : https://source.android.com/docs/core/architecture/bootloader/fastbootd#dynamic-partitions

What else ?

mr_growl

I flashed lineage 19.1-20231014-nightly-bonito-signed (which the wiki said should have android 12.1):

Android Version: 12 (according to the running system on the phone)
Lineage OS Version: 19-20231014-NIGHTLY-bonito
Phone Version: bonito
Phone Carrier: Amaysim (Optus)
Country: Australia

VoLTE is working just fine.

atarilinux

@Eric-H

What you have stated above is correct to the best of my knowledge. Here is the other part from the QA call:

*Source Material - Not Image
*Information on image build process, but not how to install it
*Built on top of latest Android 12.1 version for the Google Pixel 3a, but build not completed

So....it looks like we need to:

Finish the build (This part is the least specific. Finish what? This is the main issue due to it not being specific. Maybe it is only the retro-fitted partition issue? A lot of data may need to be checked to see what is complete. Here is the bottleneck in completing development.)
Build the image from source
Install image on the Google Pixel 3a

What we have currently:

Information on the retro-fitted partition and possible install process
Confirmation on VoLTE access for the Google Pixel 3a from other alternative OS's and carriers (It is possible!)
Specifically what to look for to see if the carrier supports your Google Pixel 3a (VoLTE Roaming is supported, Hardware check from carrier)

atarilinux

@mr_growl

Great news! Thanks for sharing! I think we are closer. Please see my last post to @Eric-H to see where we are now and the remaining items we will need to figure out.

ElliotLurie

@atarilinux

It seems like some data is lost from the deviceinfo file during the build process... Here's the output of unpack_bootimg after the build:

kernel_size: 18686554
ramdisk size: 6267912
os version: 12.0.0
os patch level: 2022-09
boot image header version: 3
command line args:

FPSensor

when the retrofitted partitions were implemented by pixel 3a stock rom? someone knows that? also would be nice to see if there are more devices that have retrofit to see how they merged it in the build system or what they adapted to get it working, i don remember what loop0 is to be honest