In this page is collected some practical knowledge for integrating the Jolla's official procedure for flashing the SFOS.
These are the two tools that have been reported to work on Windows for flashing AOSP into the Sony Xperia smartphones:
The Sony Emma flashing tool does not seem to be able to run also on a GNU/Linux distribution, but the XperiFirm does.
The Sony Xperia X10 II devices comes from the factory with Android 12 pre-installed since 2021:
In particular, we are interested in the European customized version:
- 1321-6453 Customized EU 59.2.A.0.463-R14C discovered on May 2022.
It is reasonable to claim that soon Jolla will need to add support for Android 12 based Xperia X10 II devices, which has been the default Android version for more than one year at the time of writing. Especially because the 12 version is also the end-of-life last image for such device.
In the Jolla flashing instructions, there is a suggestion of upgrading 11 from 10 but nothing about downgrading 12 to 11 which seems as important as the upgrading.
ℹ️ Note
Some users on the forum reported not having particular problems with SailFish OS in combination with Android 12.
Therefore, it seems that there is no reason not to go with the factory Android 12 or use XperiFirm for flashing it. Unfortunately, reality presents us with another more complex story.
Android 11 AOSP is available with XperiFirm:
- XQ-AU52_Service Exchange Unit_59.1.A.2.192-R3B for Xperia 10 II dual SIM
- XQ-AU51_Service Exchange Unit_59.1.A.2.192-R2B for Xperia 10 II single SIM
Android 10 AOSP is available with XperiFirm:
- XQ-AU52_StoreFront_59.0.A.6.24-R4A for Xperia 10 II dual SIM
- XQ-AU51_StoreFront_59.0.A.6.24-R4A for Xperia 10 II single SIM
None of these seem suitable for end-users, but they can be fine for supporting the SailFish OS.
ℹ️ Note
Some users on the forum reported not having particular problems with SailFish OS in combination with Android 12 especially about make working properly the A/GPS hardware subsystem.
Using a wide variaty of ASOP on which installing SFOS, the end-user support can be difficult and the community support can be hostile with those who do not pedantically follow the flashing instructions. Therefore, in order to achieve a kind of standardisation about the SFOS installation, I think that flash.sh should check for the correct baseband (build) before proceeding.
ℹ️ Note
the
fastbootprotocol is not able to retrieve data from smartphone partitions but just some specific variable values. An alternative protocol tofastbootis the Android Debug protocol, which is used by /e/OS for the easy-flashing procedure of the Murena best supported smartphones.
In fact, the baseband version could be retireved by fastboot with this command:
fastboot getvar version-baseband
This is the document in which is explained the procedure to bring back Sony Xperia devices working with Android:
Unfortunately only the Microsoft Windows procedure is listed. The Linux one could be easily added:
$ sudo apt-get install mono-complete
$ sudo cert-sync /etc/ssl/certs/ca-certificates.crt
$ sudo certmgr -ssl -m https://software.sonymobile.com
Despite the error message, enter Y when asked. You could be asked to do so twice from here:
* XperiFirm: a Xperia Firmware Downloader v5.6.5 on XDA Forums
then download this zip and extract the binaries for the x32 and x64 platforms:
$ url=https://forum.xda-developers.com/attachments/xperifirm-5-6-5-by-igor-eisberg-zip.5488139/
$ wget $url -O xperifirm-5-6-5-by-igor-eisberg-zip
$ unzip xperifirm-5-6-5-by-igor-eisberg-zip
Then execute XperiFirm leveraging the mono framework:
$ mono XperiFirm-x64.exe
Unfortunately, XperiFirm can download just a few AOSP versions compared to Sony Emma. Therefore I did not go with it because it asked me to download 2.66Gb of Android 12 firmware. In fact, it is the same build release that I had before the installation of Sailfish OS:
Device: Xperia 10 II (XQ-AU52)
CID: 1321-6453
Market: Europe
Operator: Customized EU
Version: 59.2.A.0.463-R14C
Size: 2.66 GB
Instead, if we are planning to bring back our Xperia smartphones to work with Android 12 only then XperiFirm is perfectly fine.
Finally, Sony Emma allowed me to downgrade the smartphone OS to Android 11 but it works only on Microsoft Windows.
The Open Source archive of the baseband build required by Sailfish OS is downloadable from here:
This link below is reported just for sake of completeness, but it does not work unless the download is started by a registered user within the Jolla shop.
Instead downloading the Android 10 binaries image does not require any credentials, and it should be immediately available:
The first link contains the sources while the other two the images which are related to the Sony Xperia 10 II.
What is above is related to Android, but to flash SailFish OS onto the smartphone, another tool is used that leverages the fastboot mode.
I have tried to erase all the partitions before re-flashing Sailfish OS, plus I flashed the secondary OEM partition:
fastboot erase dtbo_a
fastboot erase dtbo_b
fastboot erase boot_a
fastboot erase boot_b
fastboot erase oem_a
fastboot erase oem_b
fastboot erase userdata
bash flash.sh
fastboot flash oem_b ./*_v12b_seine.img
fastboot reboot
Erasing the partitions before flashing is not strictly necessary, but considering that spare images skip those blocks that are not allocated, it is the quickest way to ensure that no fragment of the previous data remains. However, that erasing process cannot be considered safe from a forensic point of view, possibly but not necessarily.
Also, flashing the secondary OEM partition is optional because flash.sh does not do it by default. However, doing this ensures us that SailFish OS will run on the correct OEM binaries, whatever the partition is selected.
In the future, having a recovery image that can fulfill its duty also having an OEM partition with a backup of the original data will be a great advantage.