Share your experience!
I updated my ZL to the .253 firmware a good bit ago ( a couple of weeks, perhaps? not sure), and I rarely ever shut my phone down, but I installed an update to an app manually and decided to reboot, which, of course, involves shutting down and then booting back up since the ZL lacks a reboot option on the shutdown menu. Well, my phone shut down fine, but on reboot, it went into a boot loop (stuck in animation, then started all over again until I held the "off" button under the back flap until it vibrated 3 times). This was a few hours ago.
I've since used the PC Companion software to repair my phone, and it did, and it's working again (still downloading apps because the notification LED still gets broken if you allow your google account to backup/restore, so I have to do it all one at a time), but of course, a repair loses all user data, so I've lost anything I hadn't backed up before this happened. Thankfully, I don't keep much on my phone, but still. This is just bad -- shutting my phone off should not be a stressful event. I should not have to worry whether or not it will boot back up! And believe me, the next time I go to shut down my phone, there will be some degree of paranoia that it might do this again! I'm glad I was within reach of my PC right then, I'll say that.
Also, I decided to visit a favorite android forum to see if anyone else had experienced this, and found several folks all with the same basic issue, so I thought perhaps I'd post about it here. At least a few others seem to feel that it has happened after the first shutdown after the .253 update. I know this is true for me, but I don't know if that really has anything to do with it.
I love the ZL, I really do. This is probably the worst thing that's happened to me since I got it a few months ago, but still -- this is pretty bad. A boot looping phone that's never been modified or messed with that's on 100% stock firmware is scary. These phones are important things we all carry -- and I carry mine as a phone first, tool second. It isn't just a cool toy, it's a communication device. I should be able to shut it down and not worry if it'll boot up when I need it to. I came to the ZL from a string of Samsung devices, and I never had any of them do this. I've had them shut down on me for no reason, but they always started back up just fine. Dead until plugged into a PC and repaired is pretty unacceptable. I've always admired Sony products, and I'm not saying Samsung is perfect (I got rid of my SGS3 for the ZL, I love this phone that much), either. I just think Sony needs to be concerned about any significant number of incidents like this.
Perhaps I'm in a really small group, though, and this was just some weird incident. I sincerely hope so, but I felt it important enough to post about it here. If anyone else has experienced this, it's probably imporant that Sony know about it for the future.
Thank you for sharing this with us and I'm glad to hear that you got it running again.
It seems that no one else have replied to this thread stating they have the very same problem but in order for me to send any feedback further on about this I will need more background and scenario information. Please post what other app's you have installed and what the uptime is. Also which build number you're running on.
I also update 10.1.1.A.1.253
After this next day as the master explained me the firmware of phone fell off/ He said me that it happens cause of i made software update/
So what should i do? Should i not update the sodtware of i phone/ As i know we should update phone for it's better work. Please help? I have this phone for a few days and i have already have this problem?
I've got the same problem. Updated to the latest firmware a few days ago (10.1.1.A.1.307). Everything went fine until I switched off the phone when there was around 17% of battery left (in stamina mode). I restarted the phone and it went to a boot loop even I forced shutting it down and reboot it again. Heard from the net that others have experienced that too and many were had it shutted down while in stamina mode. I think Sony has to investigate into this issue. I'm now charging up my phone and see if I can get it fix using PC companion. Was happy with the device but very disappointed with such a buggy update. 
hi...im using xperia zl for 3 months, than after a day update using pc companion to .67 it suddenly shut down while im playing CSR Racing... then i restart the phone again, but it only SONY logo appear, then it shut down again.... so i try to turn it on while connecting to charger, yes it will turn on normally again. but when i disconnect the charger cable, it looks normal for a while.. but when i try to open any aplication, it shut down again... so at this time, i have to conect a charger to my ZL to turn it on..it ..... just for info, i never drop my phone, neither hit it to water..., i use my phone just to browsing using chrome, check email from gmail, n play csr racing occasionally, instagram, quickpic, avg pro...
please help !!!! dont you know, in indonesia sony aftersales service is and really really bad, its a mid end phone, but they give you bad service...and if they take your phone to repair (using warranty card) we need to wait more than 1 month...so i have to use another phone, sony aftersales service in indonesia really need to repair themselves before they repair our phone...