Model Name: ZS620KL 6GB RAM 64 GB storage
Firmware Version: Android 10, security patch level: 5 March 2020
Rooted or not: NOT
Issue encountered: extremely low battery life, SIM not recognised on restart, random screen wake
Battery life fix:
Settings -> Location -> App permissions: Remove all apps from "Allowed all the time" except Find My Device.
Apps & notifications -> Recently opened apps -> See all # apps: Uninstall & disable all unwanted apps.
WARNING: Disabling certain system apps can affect functionality. Research recommended.
SIM not recognised fix:
WARNING: RISK OF DAMAGE TO THE PHONE.
Scroll to 'Take out the SIM...' in post (6th paragraph).
I would like to tell the story of how I upgraded to Android 10 and what I did to fix the problems I encountered.
First off, it took a lot of time and effort to research everything. The impression I formed was that it's really not only Asus that is to blame for every issue encountered - when, after hours of googling, I expanded my search from just the ZenFone to Android 10 in general, I could see that many other manufacturers' phones have similar problems. Android 10 was just a kick in the gut for everyone. My brother-in-law writes code for Android-based TV boxes, and he said that transitioning to A10 caused their 4-year project to be essentially scrapped - they'll have to rewrite it almost from scratch.
I've seen a lot of complaining, some downright bitter posts, swearing, threats, you name it. I believe it doesn't help. Support staff have severe restrictions on what they can and cannot say if they want to keep their job. See, if it's something that Asus messed up, they can't just come out and say, 'we messed it up'. They'll be evasive about it, which is what they're trained to do. And if it's Google itself that messed up, well, you can't bite the hand that feeds you, now can you? So they'll do the same. They're really not to blame, they're not bad people, it's just how communication in support works.
On to the story, then.
Initially, my main problem with the ZenFone 5z on Android 9 was that after a restart, it would not find the SIM card and I would have no service. Several hours of googling later, I found a workaround - a little ham-fisted, but it works. If you're still on A9 and are encountering the problem, do this:
Take out the SIM, restart the phone, reinsert the card while it's restarting, at the same time squeezing the approximate area where the SIM goes between thumb and index finger with considerable force - obviously, not tightly enough to crack the body or the screen (in my case, the sceen protector) - and concentrating on the back side. It usually takes a couple of tries. Take care not to press any of the buttons on the side while squeezing, or you'll boot into safe mode or access the boot menu.
Here, I would like to say that I'd have been content to stay with A9 had this not been a problem. I feel uncomfortable applying physical pressure to my phone, and it is a risk. Also, after the update to 10, I only had to do this once. With every subsequent restart, the maneouvre is not necessary anymore. It's still an open question whether this is a hardware or software issue, or a combination of both.
So, after months of this slightly unnerving situation, I then had to contend with the update nag screen as well. I've found a way to maybe get rid of it, but I haven't actually done this, and the solution is also for Android 8 and a different phone model, so it might not work. The forum won't let me post links, so here's the quote:
Enable developer settings.
In developer settings, scroll down to the last. Somewhere towards the last, you'll find a setting called background check, enter this setting, scroll down to FOTA service and turn off its background check.
Go back in settings to apps and notifications. Select all apps and select show system apps from the three dot menu. Scroll down to FOTA settings and turn off background activity for the app (this is under battery settings).
The time had come to apply the update. The first thing I noticed was increased responsiveness. Everything was quicker and smoother, so perfomance-wise, it's definitely a step up. I don't really game on the phone, and I've seen some posts on issues with two-finger use introducing stuttering (in PUBG, specifically, when you keep one finger on the touchscreen to run and use the other to navigate and aim - again, I only read this, haven't actually experienced it), but as I understand it, the app or even Android itself might be to blame, not 5z specifically. It's unclear, and I haven't investigated further.
Once the phone started up and things were all set, however, I noticed that it was eating through battery power like there was no tomorrow. Just with navigating through the menus, checking settings and so on, the battery app told me it would last about 3-4 hours. With normal use (I mostly use the Opera browser and apps like Quora, Messenger, some light Instagram, maybe Shazam every couple days or so), I would previously have to charge on every second day, approximately.
Naturally, I became concerned and spent a couple of hours googling. What I came up with was that the battery saver app is useless, there was no single app causing the drain; the problem lies elsewhere. Thanks to a YouTube video, it came out that a lot of apps post-update would get permission to use location permanently. To counter this, you have to go to Settings -> Location -> App permissions. There you will have three categories: Allowed all the time, Allowed only while in use and Denied. There were a ton of apps who had access to the location permanently, so I placed taxi, ridesharing, food delivery, map, sports and navigation apps into the Only while in use category, and moved everything else to Denied. At the moment, the only app I have on Allowed all the time is Find my device. I've been sober a year now, so it's unlikely I'll ever be so confused that I'd lose my phone, but you never know what can happen.
Instagram doesn't need to know where I am; neither does Facebook, Messenger, Opera, Phone, Photos, Revolut, Snapchat, WhatsApp, Viber, YouTube, Messages, Play Store, Gallery, Contacts, Calendar... I suspect that when installing these apps, their default state is set to All the time, and they didn't go through some serious vetting. Hence, they were hogging battery power in a serious way.
Now I do understand that as apps get updated, they need more performance, and regardless of raw hardware power, older OSs can't put as much capacity at their disposal, so when the new update unlocks more performance, the first thing to be affected by an upgrade is battery life. But this was really too much, and there was a lot of room for optimisation.
Next, I decided that as long as I'm already doing a deep dive into the settings, maybe there are some apps I don't need. Bloat, basically. So I went through my app list - again, spending at least an hour or two on this, because I wasn't sure what some of them did, so I had to look them up. What I deemed unnecessary, I uninstalled. Many can only be disabled; with these, I took care to empty cache and storage as well. Essential system components can probably not be shut off, and it's clear you can go even deeper into the guts of the phone - I didn't access developer settings and the boot menu, and never messed about with rooting - but I really don't have the time and patience to explore the complexities involved. Maybe one day, when I reeeeeeally don't have anything to do with my time. As it stands, I went as far into the settings as I was comfortable with and got my phone working reasonably well again, and that's enough for me. Now it has reasonable battery use. It gets me through the day, and doesn't lose more than 3-5% overnight.
It takes time and effort and patience and nerves and a lot of swearing to do all this. I'm currently thinking of just scrapping this post and going back to playing video games or watching series or doing whatever, but hey, I have insomnia, we are on coronavirus lockdown, and if it helps anyone, I can at least feel a bit better about myself. I don't blame anyone for being frustrated and impatient; I am, too, but I just keep it inside myself and always look for a solution, if there is one. The way I see it, you either dedicate yourself to solving a problem, or leave it behind you altogether. Anything else - procrastination, complaining, blaming others, going on rants against the companies, the devs, the support staff, and so on - is a waste of your time. You won't get anything out of it. So it's either this, or buying an iPhone and spending your money instead of the time and effort to fix stuff.
Back to my story.
One idiot thing that I did was trying to revert to Android 9 before trying the above. I thought I was soooo smart. I made backups to Google Drive and an SD card, downloaded the downgrade image, reverted. But the moment I tried to restore the backup, I couldn't find the option to do so. A few minutes of googling revealed why: you can't restore a backup of a higher version of Android to a lower version. Facepalm. In hindsight, it makes complete sense, this was entirely my fault. So then I decided I would try to fix the problems with A10, and here I am.
One more thing that bothered me, and still comes up in certain siuations, was the random screen wakeups. I want to make it clear that I tried many things, but the phone seems to sometimes switch on the sceen randomly. Two sources that I narrowed it down was the Lift to wake up function and the silent notifications. It's still unclear to me why they persist, but they seem to activate even when turned off in the options. The Lift to wake up thing sort of went away by itself, but I'm still having trouble when plugging headphones in and listening to music. As the phone moves around in my pocket, the screen gets activated, maybe because the music player (Musicolet) places a widget on the lock screen, and that prevents me from using the button on the earbuds to stop, skip and resume songs. I'll live with it for the time being.
Thank you for reading this post. I realise it's extremely long; I haven't written anything longer than a sentence or two for a decade or more on the internet. If I ever write again, I hope to be more concise. Also, no PS.
P.S.: No, really.
P.P.S.: What did I just say?