[Samsung Galaxy S10 ROMs, Kernels, Recoveries, & Ot] ianmacd:
[IMG="Banner"]https://www.maketecheasier.com/assets/uploads/2019/01/twrp-featured.jpg[/IMG]
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Preamble

When TWRP first appeared for the S10 range of devices, it quickly became clear that there were some major issues with the initial builds.

Many users were understandably frustrated at losing the ability to boot their device after shutting it down, and at being unable to update Magisk after installing TWRP.

A number of users took to contacting me privately for support. I answered their questions and even shared fixed images in a few cases, but the number of support requests was rising daily and I could not keep pace with the demand.

Given that the poster of the original images (Geiti94) was evidently unable to offer fixed TWRP images in a timely fashion, I ultimately took the liberty of doing so myself in a posting to the original TWRP thread as a service to the community.

Whilst this served to relieve the immediate pressure, the ongoing need to fix bugs and make further enhancements to the software made a fork of the original project inevitable, so I have taken the step of promoting it to its own DevDB project and thread here on XDA.

Credit goes to Geiti94 for conducting the time-consuming initial legwork and releasing the original builds. His is the foundation on which this work now builds. This fork in no way implies any disrespect to him, but does strongly acknowledge the need of the S10 user base to be supplied with proper, working images and timely updates.

Samsung system-as-root devices

All new devices launched with Android 9 are required to be factory-configured as system-as-root devices. The ramdisk image formerly found in boot.img is now merged with system.img.

For Samsung devices such as the Galaxy S10 series, this means that boot.img can no longer be used to root the device. Instead, Magisk is installed to the recovery partition and the user must subsequently always boot from that partition, regardless of whether TWRP or Android is desired. The device's hardware keys are used at boot time to select between Magisk-rooted Android and TWRP.

This configuration dictates that TWRP and Android share a common recovery kernel. However, because TWRP cannot function with a stock kernel, a modified kernel must be compiled from Samsung's source code. Unfortunately, this kernel is sensitive to changes in Samsung's firmware releases from one month to the next, meaning that problems can arise if a given kernel is used with firmware newer than the version the kernel was intended for.

This unfortunate situation necessitates semi-regular maintenance releases of TWRP to keep the kernel in step with the latest version of the S10 series firmware. This requirement is further complicated by the fact that any given release of Samsung's modified kernel source code typically trails the associated firmware release by anything from a few days to a few weeks.

TWRP without Magisk

If your device is currently still unrooted and running stock firmware, you are strongly advised not to proceed with installing TWRP. First root your device with Magisk, using John Wu's excellent Samsung system-as-root-instructions for patching the firmware's AP file. Only when you have completed that procedure should you return here and continue from the Image Preparation section.

If you insist on proceeding with installing TWRP to a stock device without Magisk, you will need — at a minimum — to flash a vbmeta.img with verity disabled or you will render your device unable to boot. You can construct such an image using the following command:

$ avbtool make_vbmeta_image --out vbmeta.img

Alternatively, if you don't have a copy of avbtool at hand, the following piece of shell code will do the trick on the device itself:

h=$(printf '4156423%08d1%0240d617662746f6f6c20312e312e3%0230d')
d=''
i=0
while [ $i -lt ${#h} ]; do
d="$dx${h:$i:2}"
i=$((i+2))
done
printf "$d" > vbmeta.img

Next, flash this to the vbmeta partition, using either Heimdall or Odin.

# heimdall flash --VBMETA vbmeta.img

You may then proceed with installing TWRP according to the instructions below.

Image preparation

In contrast to the original Geit94 release, these and subsequent TWRP images will not be supplied pre-rooted with Magisk. Whilst it would be trivial to offer them in this format, this kind of binary distribution of Magisk is against the terms of use laid out by Magisk's developer, John Wu.

To root the TWRP image yourself, simply use Magisk Manager to Select and Patch a File. Provide your freshly downloaded TWRP image file as the input.

Installation

You are now ready to flash the resulting magisk_patched.img image file to your device's recovery partition.

One quick and easy way to do this on an already rooted device is from a root shell:

# f=/storage/emulated/0/Download/magisk_patched.img; dd if=$f of=/dev/block/sda15 bs=$(stat -c%s $f)
1+0 records in
1+0 records out
61734912 bytes transferred in 0.426 secs (144917633 bytes/sec)

If TWRP is already installed and you are merely updating it, you may, of course, use TWRP itself to flash the new version.

If the device is not yet rooted (or even if it is), you may use Odin in Windows, but you will need to rename and tar the image first. Otherwise, Odin will not understand what to do with the image.

For example:

$ mv twrp-beyond[012]lte.img recovery.img
$ tar cf twrp-beyond[012]lte.img.tar recovery.img

And if rebooting to Windows is too disruptive, there's always Heimdall:

$ sudo heimdall flash --RECOVERY twrp-beyond[012]lte.img

Download

The latest unofficial local builds currently available are:

Android 10

G970F (S10e): twrp-beyond0lte-3.4.0-4_ianmacd.img

G973F (S10): twrp-beyond1lte-3.4.0-4_ianmacd.img

G975F (S10+): twrp-beyond2lte-3.4.0-4_ianmacd.img

G977B (S10 5G): twrp-beyondx-3.3.1-100_ianmacd.img

Android 9

G970F (S10e): twrp-beyond0lte-3.3.1-13_ianmacd.img

G973F (S10): twrp-beyond1lte-3.3.1-13_ianmacd.img

G975F (S10+): twrp-beyond2lte-3.3.1-13_ianmacd.img

G977B (S10 5G): twrp-beyondx-3.3.1-7_ianmacd.img

Official builds were also offered by me until the release of Android 10 for the S10 series, but have been discontinued. They offered no practical advantage over the unofficial builds, yet added considerably to the administrative burden. Any build for Android 10 and tagged official has not been built by me.

These builds are based on the latest version of TWRP and include a kernel compiled from Samsung's latest available source code. The kernel runs in SELinux enforcing mode and its configuration has intentionally been kept as close to stock as possible in order to provide maximum compatibility with both Android and TWRP.

The builds have been well-tested and are known to work as intended on supported firmware versions. See posting #2 of this thread for details of which TWRP builds work with which versions of Samsung's firmware.

If you later find yourself running on updated firmware that is incompatible with this kernel, you have the option of flashing and rebooting to TWRP on demand. When you are finished in TWRP, you can replace your recovery image with Magisk-rooted stock recovery and reboot back to Android.

If installing TWRP on your device for the first time or reinstalling it following a firmware upgrade, do not forget to disable file-based encryption (FBE) immediately after flashing TWRP or you won't be able to read files on /data in TWRP. To achieve this (and to protect yourself against various anti-root protection mechanisms that Samsung have booby-trapped the device with), flash the latest version of the multidisabler as soon as you have installed TWRP.

Device firmware updates

When it comes time to update your device's firmware, please follow John Wu's excellent instructions for patching the firmware's AP file. Do not skip any of the steps.

Next, use Odin to flash the patched AP file, together with the stock BL, CP and HOME_CSC files. Never leave the CSC slot empty when flashing an AP file, or your /data partition may be shrunk and your data damaged during the flash.

When finished, immediately reboot back to download mode and reflash your Magisk-patched TWRP image. Alternatively, you may replace recovery.img in the patched AP file with your rooted TWRP image, thereby avoiding the need to separately reflash TWRP afterwards:

$ tar f magisk_patched_twrp.tar --delete recovery.img && tar rf magisk_patched_twrp.tar recovery.img

Lastly, boot to TWRP and reflash the latest version of the multidisabler. Note that your first boot to TWRP after installing new firmware may just run a post-installation recovery script that wipes /cache, so you may need to trap the automatic reboot that follows and boot to TWRP a second time.

Do not skip rerunning the multidisabler, as flashing new firmware will have re-enabled critical security features that you must now re-disable.

Frequently Asked Questions

Q. I've just updated my G97[035]F device to ASIG firmware and now I can no longer boot to TWRP, which means I also can't flash the multidisabler to keep encryption disabled. What can I do?

Samsung's new ASIG firmware for the S10 series has proven to be incompatible with any kernel compiled for an earlier version of the firmware. You are urged to upgrade to TWRP version 3.3.1-10_ianmacd or later to avoid problems with this firmware.

If you are unable or unwilling to do this, the following procedure should be observed:

If you simply upgrade to this new firmware as usual, by patching the AP file with Magisk Manager, you will find yourself unable to boot TWRP afterwards, and therefore also unable to flash the multidisabler. This is a potentially dangerous situation, as it can lead to data loss if not properly tackled.

1. When flashing the new full firmware in Odin, use the BL file from the previous ASH6 firmware, not the one from ASIG. Include the latest version of TWRP as recovery.img in the AP file, as per usual.

2. After flashing the firmware, reboot to TWRP as usual. Flash the multidisabler and any other files you usually flash as part of the post-upgrade process.

3. Make a copy of the ASIG BL tar file. From this copy, either remove vbmeta.img or replace it with a benign copy constructed as per the #vbmeta note in this group.

4. Use Odin to flash your modified BL file, together with a Magisk-patched copy of the stock ASIG recovery image in the AP slot.

5. Reboot to rooted Android.

If you follow these instructions, you will successfully upgrade your device to ASIG firmware, whilst retaining a decrypted /data file-system, etc.

TWRP can still be used on demand, but you will need to add the swapping of the bootloader to your existing procedure for switching between stock and custom recovery. Or you can simply wait a couple of weeks for Samsung to release updated kernel source code for ASIG, at which time I will issue new builds of TWRP.

Lastly, there are apparently some new TWRP builds currently doing the rounds that deal with the ASIG incompaibility issue by including a kernel hacked together from a mixture of S10 and Note10 source code. Approach such hybrids with due caution.​

Q. I don't want to dual-boot Android using the custom kernel from my TWRP image. The latest TWRP kernel is often compiled for older firmware. Even if there are no visible issues using this older kernel, I'm probably missing out on improvements and fixes made in the latest kernel. Is there really no other way to run TWRP on these devices?

A. Actually, there is another way and it's actually simpler than and therefore preferable to dual-booting. You can opt to simply flash and boot TWRP on demand, leaving a Magisk-rooted stock recovery on your device the rest of the time.

For example, the following simple script could be used to toggle your recovery partition between stock and TWRP images.

Copy the following (not as the superuser) into a file, for example /storage/emulated/0/switch-recovery:

#!/bin/sh

twrp_img=/storage/9C33-6BBD/twrp-3.3.1-4.img

# Path to ext. SD is different in TWRP.
stock_img=/external_sd/recovery-asf3-magisk.img

if [ -f /sbin/magisk ]; then
# We're in Android: Switch to TWRP.
#
infile=$twrp_img
su='su -c'
else
# We're in TWRP: Switch to Android.
#
infile=$stock_img
fi

$su dd if=$infile of=/dev/block/sda15 bs=$(stat -c%s $infile) && reboot recovery

Then run it in Android in a terminal session:

# sh /storage/emulated/0/switch-recovery

It will flash your TWRP image and reboot the device to recovery. If the TWRP image is rooted, you'll still need to press the usual key combo to force pass-through to TWRP.

Do your work in TWRP and then run the script again from the TWRP terminal. This time, it will reflash your stock recovery image and reboot again to recovery. There's no need to press the hardware keys this time, because you are booting to Magisk-rooted Android.

Obviously, you must change the paths in the script to match where your own images are stored.
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Q. Somewhere in upgrading my firmware, rooting and installing TWRP, my /data file-system mysteriously shrank to a fraction of its former size and appears to have been wiped. What happened? Is TWRP responsible for this?

A. No. This appears to be a side-effect of using Odin to flash an AP file to these devices with the CSC slots left empty. Never flash a full AP file on this range of devices without also filling at least the HOME_CSC slot. It is safe, however, to flash only a recovery image in the AP slot.

To attempt to repair the damage, you need to boot to TWRP, select Advanced Wipe, tick Data, select Repair or Change File System followed by Resize File System. Your /data will return to its former size, but you will probably find you have lost some data. Restore a /data back-up afterwards to be sure of having all your data.
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Q. When I mount /system and execute commands in the TWRP terminal or over adb, I get a lot of noise about problems with the dynamic linker.

A. This problem is fixed as of version 3.3.1-1_ianmacd.

It is caused by /etc/system becoming a symlink to itself when /system is mounted, resulting in infinite recursion when followed.

The screen on your text is just a warning, not an error. Your commands are still being executed.

Nevertheless, noise annoys, so you can silence the warning by pasting the following commands into the terminal (with thanks to John Wu):

# mount --move /system /system_root && mount -o bind /system_root/system /system

Q. My favourite zip doesn't flash properly using this TWRP. Someone said these TWRP builds are to blame, because they don't include BusyBox. Why don't you fix them?

A. Because there's actually nothing wrong with them. It's the installer code of your favourite zip that is broken. TWRP is merely exposing that fact. Don't shoot the messenger.

A lot of poorly written legacy installer code lazily assumes the presence of certain binaries, in particular BusyBox. However, the inclusion of BusyBox in TWRP is a compile-time option entirely at the discretion of the builder. It is not a requirement.

Not only that, but the inclusion of BusyBox in builds of TWRP targeting Android 9.0 and later is officially deprecated. Maintainers of such devices are instead advised by the TWRP team to use Toybox, and these builds for the S10 series comply with that advice. Furthermore, it's actually currently impossible to even build an official TWRP image for these devices with BusyBox included. Compilation of TWRP on the official build server will fail if this is attempted.

In short, the assuming BusyBox's presence on the device is unsafe and your favourite zip's author should fix his installer code. Supply him with an installation log and politely ask him to rewrite the installer code to be independent of this historical TWRP implementation detail.

Anyone who maintains that TWRP is broken without the inclusion of BusyBox is simply either unwilling or unable to grasp the facts.
​

Q. When I boot to Android, I can no longer log in. Why?

:victory:

A. Probably because of a mechanism called rollback protection. What has most likely happened here is that you have previously booted the device from a boot image with a later security patch level than the one from which you are trying to boot now.

As an example, let's say you are currently booting your device from a TWRP image with a security patch level of 2019-06. Then, Samsung issues a firmware update with a patch level of 2019-07. You update to that firmware, but immediately replace the stock recovery image with your trusty TWRP image and keep booting from that. Everything continues to work as it did before.

However, one day, you accidentally boot the device from the boot partition instead of the recovery partition. The device predictably comes up unrooted, but more significantly, it has now been booted from a (stock) boot image with a patch level of 2019-07, a fact that the device has now also committed to memory.

If you now reboot from the recovery partition, you will find that Android will no longer allow you to log in when the lock screen appears. This is because you are attempting to boot from an image with a patch level (2019-06) that is now earlier than the latest one previously used to boot the device (2019-07). Android considers this insecure and will not allow it. This mechanism is called rollback protection.

The simplest solution and the one with the least negative impact is to update the security patch level of the TWRP image to match that of the latest image used to boot the device. You can achieve this using magiskboot unpack -h or with AIK.
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Links

TWRP source code for Android 9.0

Unofficial device tree for the G970F

Unofficial device tree for the G973F

Unofficial device tree for the G975F

Unofficial device tree for the G977B

Combined kernel source code for the G97[035]F

Kernel source code for the G977B

Telegram group

XDA:DevDB Information

TWRP for Galaxy S10 Exynos series, Tool/Utility for the Samsung Galaxy S10+

Contributors

ianmacd, Geiti94

Version Information

Status: Stable

Current Stable Version: 3.4.0-4_ianmacd

Stable Release Date: 2020-11-17

Created 2019-04-25

Last Updated 2020-11-17