[Samsung Galaxy A3, A5, A7 (2017) Questions & Answe] astartav:
Hi!

So it appears I have soft-bricked my phone. At least I hope this is a soft one, but looks harder and harder with every minute.

What I did:

- I have an A5 2017 initially running Android 8.0.0 build A520FXXUGCTKA.

My plan was to install Lineage for MicroG on it. I followed the instructions on the Lineage website, encountered immediately an absence of OEM unlock button, solved it with flashing latest stock ROM with CSE which also reset the device and doing the date/time trick (+- 8 days), after which OEM unlock appeared and I had both it and USB debugging on.

So I proceeded to install TWRP and was able to successfully boot into it, after which I followed the next fatal steps:

Now tap Wipe. <<did this

Now tap Format Data and continue with the formatting process. This will remove encryption and delete all files stored in the internal storage. <<did this, and it suddenly gave me a bunch of errors about being "unable to mount /data"

I disliked this and decided that I have to solve this before proceeding to step 3 of the guide. So I found somewhere a solution to go to Advanced Wipe, select the Data partition and repair it, which I did, but after this step I think it recommended to reboot the phone, which I unfortunately did... and I was stuck in Samsung boot with only the logo loading. I panicked and immediately tried to go back to recovery, which stopped the loop and game me the red message Only officially released binaries are allowed to be flashed.

So the status of the phone right now is:

- I cannot go into recovery mode anymore. It gives the red message about official binaries.

- Phone doesn't load into system either. It again gives the red message.

- I can go into Download mode and see the following status:

ODIN MODE

DOWNLOAD SPEED: FAST

PRODUCT NAME: SM-A520F

CURRENT BINARY: CUSTOM

( I did not actually go to step 3 of the guide and try to upload the custom ROM. But I suspect this is because it now sees the ROM as changed/damaged)

SYSTEM STATUS: Official

RMM STATE: Prenormal

(This line was absent when I managed to turn on the OEM unlock finally. Now it's back)

FRP LOCK: OFF

Secure Download: Enabled

- I cannot upload ROMs via Odin anymore. The device isn't seen by it with Download mode like before. The drivers were installed by me previously and I was able to upload via Odin. I tried to reinstall them with zadig, but instead of 2 entried named Gadget Serial like before, zadig now only sees one Gadget serial and one Unknown device #1.

I tried to flash ROM in parts to the partitions directly (binaries, img) via Heimdall (using phone.pit mapping I downloaded a bit earlier via Heimdall). Heimdall said that it was a success on each download part, but also wrote 0% near the progress and it seems that it did nothing.

To me, phone looks now as if it sees its ROM as damaged, but ignores any attempts to get anything on it anymore. Which is logical because it seems to have either locked itself in a new state or restored to the state where the USB debugging and OEM unlock are not turned on. And I can't obviously get the system to load to turn them on.

Maybe somebody encountered a similar situation and knows how to get it out of this state or what this might be?