DISCONTINUED [TWRP] Samsung Galaxy A20 Custom Recovery (Android 9)

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physwizz

Senior Member
Sep 16, 2013
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997
Sydney
steps

Installation Instructions.
There is never only one way to do anything. The following steps have worked for me.
Before you start, make sure you have rooted the A20
https://xdaforums.com/android/development/root-samsung-galaxy-a20-rooting-guide-t3954872
This part may not be necessary if you're recovering from a crash.

To install TWRP
1. Download the U2 custom recovery from here
https://androidfilehost.com/?fid=1899786940962574261
2. On the PC rename the unpatched recovery as recovery.img
3. Use 7zip to make it into recovery.tar
(right click and choose add to archive)
4. Use 7zip to add your patched boot.img to recovery.tar
(right click and choose add to archive and choose recovery.tar)
5. Download vbmeta.tar from here (https://xdaforums.com/showpost.php?p=80188834&postcount=237) and extract vbmeta.img
6. Use 7zip to add vbmeta.img to recovery.tar
(right click and choose add to archive and choose recovery.tar)
7. Install recovery.tar to ap slot using Odin.

If you are getting messages about being unable to flash the recovery try this.
https://xdaforums.com/showpost.php?p=80216465&postcount=276

8. Boot the A20 into TWRP and mount everything that you can.
9. Format Data (not just wipe) - this will remove the encryption of the data partition.
10. Flash this zip View attachment Disable_Dm-Verity_ForceEncrypt_08.18.2019.zip
11. Reboot into Recovery. It may reboot into download mode. If it goes to TWRP skip step 12. If you already have a backup, you can go to step 16.
12. On the pc install recovery.tar to ap slot using Odin.
13. Reboot phone and re-enter all data.
14. Reboot into Recovery.
15. Backup only 3 parts: boot, data & system (not system image)
16. You can now restore boot, data & system from TWRP after any crash, but you may need to forget your wifi and go back in to it.

You can now move on to installing a new GSI ROM .
It you get stuck you can come back to Samsung by using your backup.
GSI ROMs are here.

https://xdaforums.com/android/development/gsi-galaxy-a20-t3964546
 
Last edited:

jajk

Senior Member
Jul 18, 2014
1,535
1,651
Android Image Kitchen can unpack TWRP for Samsung S9 (Exynos version) which is fairly similar to our device.
I switched over the kernel and charger files, changed the recovery fstab to match our device plus a few other device specific files and repacked it and tarred it. Odin happily flashed it but the phone would not reboot out of download mode and had some negative message about a Custom Recovery.......reflashed the stock recovery and now back to square one.
I have used this technique before with success but there is a lot more protection on these newer phones that I am not familiar with getting around.
Anyway, it is still a potential way of gaining a TWRP for our device short of compiling one from scratch - just needs a few eyes and brains to have a poke around:)
 
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physwizz

Senior Member
Sep 16, 2013
4,387
997
Sydney
Android Image Kitchen can unpack TWRP for Samsung S9 (Exynos version) which is fairly similar to our device.
I switched over the kernel and charger files, changed the recovery fstab to match our device plus a few other device specific files and repacked it and tarred it. Odin happily flashed it but the phone would not reboot out of download mode and had some negative message about a Custom Recovery.......reflashed the stock recovery and now back to square one.
I have used this technique before with success but there is a lot more protection on these newer phones that I am not familiar with getting around.
Anyway, it is still a potential way of gaining a TWRP for our device short of compiling one from scratch - just needs a few eyes and brains to have a poke around:)
How did you get a copy of the stock recovery?
 
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physwizz

Senior Member
Sep 16, 2013
4,387
997
Sydney
Android Image Kitchen can unpack TWRP for Samsung S9 (Exynos version) which is fairly similar to our device.
I switched over the kernel and charger files, changed the recovery fstab to match our device plus a few other device specific files and repacked it and tarred it. Odin happily flashed it but the phone would not reboot out of download mode and had some negative message about a Custom Recovery.......reflashed the stock recovery and now back to square one.
I have used this technique before with success but there is a lot more protection on these newer phones that I am not familiar with getting around.
Anyway, it is still a potential way of gaining a TWRP for our device short of compiling one from scratch - just needs a few eyes and brains to have a poke around:)
After hitting dead ends with Mac and Windows, I succeeded in installing Android Kitchen on Ubuntu and unpack the s9 image.
Next step is to try to modify it to fit the A20
Hmmm...
 

physwizz

Senior Member
Sep 16, 2013
4,387
997
Sydney
@jajk
AIK now wants an update-script and I can't repack the recovery.img without one.

Edit: went back to the Mac and worked it out.
Didn't install though.!!@
 
Last edited:

I don't actually have the device yet. I will probably buy it in like two weeks (but i won't make nothing to it once i get bored, my parents will kill me if i brick it lol).

I can build TWRP, but i only have LOS 14.1 source (i'm not sure if that version of the source can work for a device with Android Pie).

I'm also a little bit noob on this.
 

physwizz

Senior Member
Sep 16, 2013
4,387
997
Sydney
I don't actually have the device yet. I will probably buy it in like two weeks (but i won't make nothing to it once i get bored, my parents will kill me if i brick it lol).

I can build TWRP, but i only have LOS 14.1 source (i'm not sure if that version of the source can work for a device with Android Pie).

I'm also a little bit noob on this.

???
 
Helpful Info

Download Odin Flash Tool For Android Phone, Then Extract It
Now Download >> TWRP Recovery



Then Go To Settings >> About Phone >> Tap On Build Number 5 To 7 Times You Will See Developer Option

Now Tap On Developer Option >> Then Enable USB Debugging And Also Enable OEM Unlocking





Now Boot Your Smartphone In >> TWRP Recovery Mode

To Boot Phone In Recovery Mode You Have To Turn Of Your Smartphone Then Press Volume Up + Power Botton Together To Turn On >> Recovery Mode

Then Select >> Reboot To Bootloader, After Some Time You Will See Downloading Mode

Now Cannect Your Smartphone To Computer Using USB Cable, Then Open >> Odin Flash Tool In Your PC

Now ID:COM Tab On Your Odin Will Turn Blue Which Means Your Phone Is Successfully Recognized By Odin Flash Tool, If It Doesn’t Reconnect Your Device And Check Again

Now Tap On >> AP Button On Odin Flash Tool And Select >> TWRP Recovery For Smartphone You Downloaded Earlier

Now Tap On >> Start Button
After Some Time You Will See “Pass” Button On Screen, It Means TWRP Recovery Successfully Installed On Smartphone
 

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