50.1.A is Oreo, so thats great! Just repeat the steps, but don’t flash TWRP, Boot TWRP
fastboot boot twrp.img
oh no - just made a mistake flashing with emma.
I flashed the firmware update 
Now going to flash software update 50.1.a which erases user data.
My phone is still not coming on after this seems like in a loop, grey screen bright blue screen
After flashing with Emma , do I press the vol down + power to boot into recovery or just power on to start normally? Pressing just power on send it into a cycle of grey screen, then bright ocean green and it goes on!
It should boot after emma…
so just disconnect once emma is finished.
The green light is still on even when emma is finished and the cable plugged in.
so I would just take the cable off and press power on button?
Unplug and power on.
i did it and still the same, starts with lines on the screen and then goes black but the screen is still illuminated, shows nothing, then just goes in a loop black screen, grey screen, bright ocean green screen … on and on
I’m sorry you experience such problems, i’m almost out of ideas, exept…
Sony also has open source android version, AOSP (Android open source project). This verson can be flashed using fastboot. Since you are having trouble with emma, i suggest you try this. Flash this version here follow the steps carefully.
… alternative (xda-developers) » Unable to get xA2 in fastboot mode (Quotes below)
Blue LED = Fastboot mode
Green LED = Flash mode (for reflashing stock firmware with XperiFirm in case EVERYTHING is broken)
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Install these drivers (on your Windows 7 Laptop) » Universal ADB Drivers One size fits all Windows Drivers for Android Debug Bridge.
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When in Fastboot mode, go to device manager, there is an Android device in there (may also be called MTP device). In the device manager, install a new driver for that and use the ADB driver from C:\Program Files (x86)\ClockworkMod\Universal ADB Driver.
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Windows will tell you that it’s the wrong driver. Install it anyway and Fastboot will recognize your XA2 now.
If it won’t work, after that just go to devices and printers and delete Xperia XA2. It will work.
Else, after installing 15 seconds, inside device manager, update the driver of your phone (or mtp device), select local, then Android device, then fastboot. Disconnect the phone and reconnect as before (volume down)
Fastboot is VOL. UP (on this device)! (Not vol. down)
So basically turn off the device, hold Vol. UP and simply connect to USB, hold Vol. UP until LED is steady blue and you are set.
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Note:
VOLUME UP activates fastboot
and
VOLUME DOWN enables flashmode and/or recovery mode
… alternative (LineageOS for microG) » LineageOS for microG has a relatively recent version of Oero Lineage 15.1 from 27.02.2019. The installation processes of TWRP Recovery and lineage-15.1-20190227-microG-pioneer.zip > are the well known …
Hi
When I used Emma I had no choice, only one rom available for me to install… (and no request to create an account). Then I repeated /e/ installation procedure (and installed from pen drive ) without trying lineage. And the device started with /e/ (whereas when the installation failed, my phone did not boot, stuck in a loop) .
I am sorry… I felt your pain when I could not progress and thought that my phone was bricked (then I discovered that Emma was great) … I apologize, but my knowledge is limited and I can only share my experience with you
I hope everything goes right soon
Thanks for message.
I’m just stressed as there are vertical lines on the display which I read somewhere that it means stress to the display due to flashing. I just brought this phone and I don’t have another phone.
I really sympathize… (even if I have to admit that I kept my old phone until I was sure I could switch to /e/)
Any good news?
Thanks.
My old phone completely broke so had to buy a new this new one.
I am trying to update my win 7 laptop and then try Emma again. It seems there is some problem flashing from emma, even though it says successful but still the phone does not boot up after the flash by emma. Just blank screen and lines. Someone said that they had blank screen and lines before but after flashing by emma it was ok.
So will give another try using emma. Then looking into doing a stock rom flash from here:
https://xperiastockrom.com/flash-sony-xperia-stock-rom
The last thing I want is to buy another phone which I just cannot afford so really hope it works.
Ok, seems I’ve tried everything and the screen comes up the same way everytime. After much looking online I came across this:
https://www.reddit.com/r/LineageOS/comments/c97kx5/xa2_dual_screen_fail_by_los_16/
This is very similar to what I’m facing. Any suggestions please, anyone? @sonyxa2 @andrelam @archie @Manoj
Were you trying to downgrade from Pie to Oreo. While testing our Pie code we saw bootloops on multiple devices when trying to downgrade the OS. The solution was to revert to Stock Pie builds. Then installing latest TWRP and then for /e/ also the build had to be a Pie build.
The support from sony support sonymobile means:
Can I downgrade to an earlier Android version?
No. It is not possible for you to downgrade an Xperia device to a previous Android version. Our service centers are also unable to perform such a downgrade
That must be a peculiarity of Sony? A StockROM downgrade for my LG phone never caused any problems.
Tried this? Use vendor files 8.1, sdk 4.4.
Yes, but could not do it with emma software, @robined can (emma suggests 50.1 thats Oreo) so, he must be on Oreo. Reason i suggest AOSP is that this will flash Sony vendor stuf also.