[Samsung Galaxy S10/S10+/S10 5G/E Cross Device Deve] byteXpression:
Samsung S10 LOS17 Installation Guide (for all having trouble with boot loops during the setup or partially enabled encryption, etc.)

Prepare device with latest Stock Firmware:

Boot device into Bootloader (connect the USB cable and quickly hold Volume-Down and Bixby or hold Volume-Down and Power until the device reboots and quickly hold Volume-Down and Bixby).

Install latest Stock BL, AP, CP, (Home_)CSC (and don't uncheck Auto Reboot in Odin options).

The device will reboot, erase some data and start normally (again). Be patient to let it boot (takes approx. 2 minutes).

Execute initial device setup and unlock the Bootloader:

Enable WiFi (important for the OEM Unlock Check).

Skip as much as possible until finished (as data will be erased again).

Go into Settings and enable Developer Options (Software Information -> hit 5 times on Buildnumber).

Go into Developer Options and enable Bootloader in OEM Settings (if it is greyed out, you are in the right state, if not, reboot and check again).

Shutdown.

Flash TWRP:

Boot device into Bootloader (see instructions above).

Rename the twrp-beyondXlte-3.3.1-101_ianmacd.img to recovery.img and tar it with 7-Zip (twrp-beyondXlte-3.3.1-101_ianmacd.tar).

Use Odin to flash the twrp-beyondXlte-3.3.1-101_ianmacd.tar via the AP slot (uncheck Auto Reboot in Odin).

Reboot to Bootloader again and continue with flashing vbmeta_disabler.

Flash vbmeta_disabler (important, because otherwise the boot to TWRP will fail with security check errors):

Boot device into Bootloader (see instructions above).

Extract from vbmeta_disabler.zip just the vbmeta.img and tar it with 7-Zip (vbmeta_disabler.tar).

Use Odin to flash the vbmeta_disabler.tar via the AP slot (uncheck Auto Reboot in Odin).

Reboot to Recovery (hold Volume-Down and Power until the device reboots and quickly hold Volume-Up to boot into TWRP).

TWRP may run initial setup scripts and power off the device. If this is the case, simply reboot into TWRP again and continue with flashing multidisabler via TWRP.

Flash multidisabler:

Boot device into TWRP Recovery (hold Volume-Down and Power until the device reboots and quickly hold Volume-Up).

Format Data (acknowledge with yes). This step is necessary as the files are encrypted within the "data" partition.

Wipe Dalvik, Cache, data and System partition.

Connect to the PC via the USB cable (if not connected already).

Wait for the device to become available (you may enable and disable the ADB sideload feature in order to enable device detection).

Copy the multidisabler-samsung-2.2.zip to the internal storage of the device.

Install (flash) multidisabler-samsung-2.2.zip.

Optionally prepare for FDE (Full Disk Encryption):

Unmount the data partition.

Goto Advanced and open the Terminal.

Enter e2fsck -f /dev/block/sda31.

For the 512 GB device there will be 122804224 blocks.

Resize with resize2fs /dev/block/sda31 122804220 (in order to make 4 blocks available for the FDE keys).

Check with e2fsck -f /dev/block/sda31 if all went well. You should see now the size of 122804220 blocks.

Mount the data partition again.

Flash LOS17 (optionally Magisk_Boot and GApps):

Copy now all other files necessary to flash (LOS, optionally Magisk_Boot and GApps) to the internal storage of the device.

Install (flash) LOS17 (lineage-17.1-20200205-UNOFFICIAL-beyondXlte.zip), optionally Magisk_Boot (beyondXlte-boot-magisk.img) and GApps (open_gapps-arm64-10.0-pico-20200207.zip).

Reboot to System (without installing TWRP as app, you can change this in TWRP settings so that you don't get asked anymore).

Optionally install Magisk Manager:

Once back in the system, install MagiskManager-v7.5.1.apk and let it finish finalization tasks.

Optionally finish FDE-Encryption (root is required for this step):

Use adb and pull the fstab (/vendor/etc/fstab.exynos9820) to the PC.

Edit the following line in the downloaded fstab.exynos9820 with an editor:

/dev/block/platform/13d60000.ufs/by-name/userdata	/data	ext4	noatime,nosuid,nodev,noauto_da_alloc,discard,journal_checksum,data=ordered,errors=panic	wait,check,encryptable,quota,reservedsize=128M,length=-20480

to

/dev/block/platform/13d60000.ufs/by-name/userdata	/data	ext4	noatime,nosuid,nodev,noauto_da_alloc,discard,journal_checksum,data=ordered,errors=panic	wait,check,encryptable=footer,quota,reservedsize=128M,length=-20480

and save it as fstab.exynos9820.FDE to the PC.

Use adb and push the changed fstab (fstab.exynos9820.FDE) to /data/media on the mobile device (as we need a directory which is mounted rw as temporary location).

Enable the Terminal via Developer Options (if not done already) on the mobile device.

Open the Terminal on the mobile device and enter "su" in order to get to a root shell. Allow root priviliges via Magisk (when asked).

Remount the vendor partition read/write (mount -o rw,remount /vendor).

Move (backup) the existing fstab (mv /vendor/etc/fstab.exynos9820 /vendor/etc/fstab.exynos9820.bak).

Move the new FDE enabled fstab from the temporary location to the vendor partition and rename it accordingly (mv /data/media/fstab.exynos9820.FDE /vendor/etc/fstab.exynos9820).

Reboot (as adviced by [MENTION=1342004]Bunk[/MENTION] see thread #538).

Now your device is ready to be encrypted (via Settings -> Security -> Encryption).

Load your device at least to 80% and have it plugged in to the USB cable.

Hit Encrypt device.

The device will reboot now and encrypt your data.

Done!

As optional / additional step you can get rid of the annoying "bootloader unlocked" and "not running Samsung software" warning messages during boot time. See post https://xdaforums.com/showpost.php?p=81770511&postcount=561 for further reference.

Please note:

This installation guide is for "fresh" installations. You can skip steps for existing installations based on what you need.

If your device does not boot anymore, it is always good to go back to step 1.

Be carefull not to wipe data if you are running a production device with productive data. If so, backup and restore your data partition accordingly, before you format and wipe!

You can also do other steps based on your discretion (how you want to change/edit the fstab of your device for example).

For me, the adb command works better than doing it on the device via Terminal with a small screen.

Credits also go to [MENTION=9939022]flunkyball[/MENTION] for his useful post about editing the fstab (so I added this step to the handling directions above as it provides a solution if the multidisabler was executed without the "FDE footer" patch in the first place).

Added multidisabler and vbmeta_disabler for your reference (as I got asked so many times). Please check for updates on the official XDA threats for these files and/or the installation instructions from Ivan on the very first page - as things change over time with new versions. ;)