Status update:
As it happens, I took the opportunity of having the phone on the dev channel to re-test an application that typically froze the GUI (the app called "Steps" -- I already opened a bug report on that specific issue). Turns out the behaviour was the same on v763, so I wanted to force a power cycle by rebooting the phone on the recovery image (Power + Vol+).

But instead of the recovery menu, I was greeted by the spiralling animation: the phone was clearly installing something. When it finished rebooting, I was back on OTA-20, and both SIMs were still active!

Following @DPITTI suggestion, I also removed v763 from the upgrade history.

I'll now mark this post as "resolved". Many thanks to all those who contributed.

@alter Thinking back about the whole sequence, I'm a bit concerned that my first failed attempt at flashing UT (before adapting the udev rules) may have left the phone in an "unexpected" state, which in turn caused the 2nd flashing attempt to fail with these ominous error messages.

It is perhaps best at this point that use TWRP again to put Android9 back on the phone (in both slots), make sure the phone is bootable again, and retry the whole 'ubports-installer' process again.

Just upgraded to OTA-20: the upgrade process itself went flawlessly, but the SIM card in slot #1 is no longer detected!

• during startup, I'm prompted for only one PIN code (the prompt no longer identifies the SIM, but the code only matches SIM #2)
• in "settings | mobile", only one SIM and matching operator is listed (the one for SIM #2)
• same thing in the top-of-screen quick access bar
• "setting | about" reports OTA-20

Is there any information I could collect on the phone to help troubleshoot this?

Problem has been resolved -- phone is now running UT OTA-19 stable.

Details about the fix in the device-specific post (see URL in previous post). I'll now mark this one as resolved as well.

Many thanks to all those who helped.

@dpitti The device initially came with Android 8.1, but I flashed it with v9 as recommended before proceeding with the UT installation.

Hello,
I've received the new phone and I'm trying to follow @magnargj suggested procedure to set it up (as per this post: https://forums.ubports.com/topic/6187/ut-installation-failure/5).

The phone currently runs Android 8.1.0. I've enabled dev mode, USB debugging and allowed OEM unlock. I then restarted the phone in "Fastboot" mode and was able to successfully unlock the bootloader:

$ fastboot oem unlock

('unlock_critical', as was suggested elsewhere, was not recognized)
This reverted the phone to factory settings, so I reconfigured it and re-enabled dev mode and USB debug, and now each time it boots, the phone dutifully warns me that the bootloader is unlocked (there is also an "unlocked" status at the bottom of the splash screen).

I'm now trying to boot on the TWRP recovery image, but that doesn't work. The "fastboot devices" command does list the phone:

$ fastboot devices -l
dbXXXX                 fastboot usb:1-1

But attempting boot yields the following error:

$ fastboot boot ./twrp-3.5.2_9-0-jasmine_sprout.img
Downloading 'boot.img'
FAILED (remote: unknown command)
Finished. Total time: 0.110s

I've also tried using fastboot to query various phone-side variables (as this should be a pretty basic feature), but all variables I tried (version, version-bootlader, serialno, product, secure, is-userspace) return either "unknown command" or "variable not found"). Just to make sure, I've also tried this with different USB cables.

So I feel I'm still missing a key piece of the puzzle.

An older (2014) page about ADB and fastboot utilities claimed that 'fastboot' could do little unless the Android phone was rooted. It also said that on Nexus devices, the bootloader unlock also rooted the phone. So I installed the so-called "Root Checker" app on the Xiaomi to query its status, and it confirmed the phone is currently NOT rooted.

Is rooting the phone necessary to proceed with the Android upgrade and OTA-19 installation?
Is there something else I might have overlooked?

TIA
Ph. A.

@phandersson
Further experimental results. I just watched a tutorial video on how to root the phone (just in case), and it starts with early steps that are very similar to the ones I followed, so I tried those as well:

• enable dev mode + USB debug (already done, obviously)
• connect phone to PC
• type "adb devices" => device is listed:

$ adb devices -l
List of devices attached
dbXXXX                 device usb:1-1 product:jasmine model:Mi_A2 device:jasmine_sprout transport_id:2

• type "adb reboot bootloader" to reach fastboot: the phone does reboot and reaches the fastboot splash screen
• use fastboot to boot on TWRP image -- this time, the message was different (although it still doesn't work):

$ fastboot boot ./twrp-3.5.2_9-0-jasmine_sprout.img
Downloading 'boot.img'
FAILED (data write failure (Cannot send after transport endpoint shutdown))
Finished. Total time: 0.850s

And indeed, the fastboot environment appears to have crashed: the fastboot splash screen is gone, and the phone displays a short text message: "press any key to shutdown" (pressing power then reboots the phone).

As the message could hint at a data transmission problem, I tried the same procedure with the other USB-C cable, and this time the output for the last step was:

$ fastboot boot ./twrp-3.5.2_9-0-jasmine_sprout.img
Downloading 'boot.img'
FAILED (remote: unknown command)
Finished. Total time: 0.012s

So, similar to the behaviour described in my initial post above. But I'm a bit concerned by this lack of repeatability...

@magnargj Yes, that's correct. Either 'volume down' + 'power' or "adb reboot bootloader". Same result in both cases.

Following the suggestion of a nice troubleshooting page about the "unknown command" issue, I also replaced the 'android-tools' RPM I was using (I'm on OpenSUSE Leap 15.2) by the official Google SDK ZIP file.

After doing this, the "fastboot boot twrp.img" command issued a different message ("sending twrp.img...") and just hung.

I'm also confused about this Xiaomi-specific unlock process. I found their FAQ (here: https://c.mi.com/thread-2262302-1-0.html) and in there they say: "For Android One users, please check out the unlocking tutorial in your device subforum. You don't have to go through the procedures mentioned here." They also say (further down): "How to check whether the bootloader is locked/unlocked? [...] An "Unlocked" word will be shown when booting." which is already the case on my phone.

OK -- many thanks to "Shou" and "Kisekinopureya" who helped on Telegram.

First suggestion was to run "./fastboot flashing unlock_critical" (after having flashed stock Android 9, but before starting the UPI). That turned out not changing anything.

The second suggestion was to wipe user data and cache using "./fastboot -w" (once again, before starting the UPI), and this did the trick

My phone now happily runs UT!

Hello,

In a recent post dated Nov. 20, @magnargj mentioned that applying OTA-20 on his Mi A2 caused a problem with the 1st SIM slot, which he resolved by moving the card to the 2nd slot.

I'm currently using both slots (private + professional SIMs), which works fine on OTA-19, and I would like to know what to expect before deciding to apply OTA-20.

• Can anyone confirm or deny the issue with dual-SIM support on the Mi A2 under OTA-20?
• If confirmed, is there a workaround (that preserves dual-SIM functionalities)?
• If confirmed, is this issue tracked somewhere?

TIA

@Moem Thanks a lot for your suggestion -- I'll have a look at it.

@mschmids That's good to know -- thanks a lot for your feedback.

Hello everyone,
I currently use (as secondary device) a Xiaomi Mi A2 that I installed with UT 16.04 (currently at OTA-25). I can't complain about the base OS -- that has been very stable and enjoyable to use (including the dual SIM support, one of the reasons I selected that phone to begin with). But its interactions with some of the hardware components are far from satisfying:

• the camera app is really hit-and-miss: from time to time, it's able to take a picture and save it, but most of the time it just freezes while doing so
• similar story with the GPS: uNav and OSM Scout start up fine. In most cases, uNav eventually gets a fix on the satellites and shows me my position, but when I move, the app soon stops updating my position
• I also tried to use Steps (step counter), but there as well, it may capture the first few steps, then either stops refreshing the count, freezes, or even gets the phone completely frozen

All in all, I get the feeling the apps themselves are excellent, but the lower-level drivers that implement the interface with the hardware are far from reliable (at least on the 'jasmine_sprout' platform).

Hence my question(s) to the community:

• is this experience rather typical, or just the sign that I selected a poorly supported phone model?
• if not typical, can you suggest a phone model where all these applications are known to work reliably enough to base your daily activities on? I would like to continue experimenting with UT, but preferably with better results than on the Xiaomi
• also important to me is dual SIM support -- I've looked at the phone models recommended for Focal, but none of them seemed to offer it. Any suggestions?

Side question: I remember reading in these forums that the upgrade to Focal was a pre-requisite for the UT phone app to be able to take calls through a Bluetooth headset (such as a car-kit or motorcycle helmet headset). Has there been progress on this?

Thanks in advance for any insight or advice on any of this.

After retesting yesterday and today, issue no longer manifest itself (don't know why). And that also covers waking up the phone by touching the fingerprint sensor at the back.

In any case, thread can be marked as resolved (my apologies for the noise).

Small clarification: if the USB cable is plugged after unlocking the phone (I'm talking about the UT-level PIN, not the SIM PIN), then charging takes place as expected.

@lakotaubp Many thanks for the pointer. Problem reported as https://github.com/ubports/ubuntu-touch/issues/2076.

I applied OTA-24 yesterday. Since then, the phone no longer charges when I plug it into the PC while booted to UT. When I do, the battery icon turns green and the lightning symbol appears for about one second, then it disappears and the battery icon turn white again. If I let it plugged in for hours, the battery charge doesn't increase.

Turning the phone off and plugging it to a regular USB charger still works, thankfully.

Another side effect of the latest update is that touching the fingerprint sensor at the back no longer wakes the phone up (not a big deal as far as I'm concerned, but a regression nonetheless).

Status update:
As it happens, I took the opportunity of having the phone on the dev channel to re-test an application that typically froze the GUI (the app called "Steps" -- I already opened a bug report on that specific issue). Turns out the behaviour was the same on v763, so I wanted to force a power cycle by rebooting the phone on the recovery image (Power + Vol+).

But instead of the recovery menu, I was greeted by the spiralling animation: the phone was clearly installing something. When it finished rebooting, I was back on OTA-20, and both SIMs were still active!

Following @DPITTI suggestion, I also removed v763 from the upgrade history.

I'll now mark this post as "resolved". Many thanks to all those who contributed.

@lakotaubp said in Dual-SIM + OTA-20 on Mi A2:

@phandersson So you are back on stable with 2 simsworking?

The 2 SIMs are working again, yes, but I'm still on "devel" (v763), and apparently unable to get back to "stable". I can select the channel, but nothing gets downloaded.

Might just be an overlap of updates between being on dev and going back to stable. Should be safe enough to ignore it and carry on the next stable update should remove it.

You mean, switch to "stable" even if nothing happens, and wait for OTA-21 to be released? I can try. Although representing heavier work, I guess I could also re-install the phone from scratch on OTA-20 using UTI.

By the way, the problem of dual-SIM support in OTA-20 is a known bug (just found out about it):

https://github.com/ubports/ubuntu-touch/issues/1879

...and a manual fix is provided in the post by "laguna66".

@lakotaubp Same behaviour after power cycle.

What's strange is that after switching back to the stable channel, the main "Settings" screen shows 1 update available (see screenshot below):

But when tapping on that line, and after "checking for updates", it still returns "Software is up to date".