[Samsung Galaxy Tab A series ROMs, Kernels, Recover] K9100ii:
This is LineageOS 17.1, which is based on Android 10, for the WiFi-only variant of the Samsung Galaxy Tab A 10.1" (2016), codenamed gtaxlwifi. LineageOS doesn't need much of an introduction - It's a well-known custom firmware/Android distribution.

I started these builds because the LineageOS builds from @Valera1978 had 2 particular significant bugs in them that were always being mentioned in posts in that thread: display backlight brightness not changeable from full brightness and the touchscreen appearing to not respond after putting the tablet to sleep. Those bugs had existed for quite a long time. @followmsi has some changes in his 17.1 device tree that fixed those 2 bugs.

These builds really became a continuation of Valera's builds after he unfortunately discontinued work on this device due to an (understandable) lack of interest, with many improvements and additional features.

I've now discontinued these 17.1 builds.

I've long ago moved onto LineageOS 18.1 and 19.1.

Very important note for those upgrading from the releases from 20210523 and 20210413 in this post: https://xdaforums.com/t/lineageos-17-1-for-sm-t580-gtaxlwifi.4059571/post-85106105

Note: I've never had any builds for the LTE variant. However, builds for the WiFi-only variant boot and work on the LTE variant, only without mobile networking (of course), GPS and vibration, so since I've allowed installation on the LTE variant in the last several builds, you can try to use my builds on it if you can go without any of that functionality.

Downloads:

Latest build from 20211116 (with security patch level 20211105):

https://drive.google.com/file/d/14ZCYYcT5b6E9zWiFNgwUP3Kxlvf-dyVn

Folder for these builds (which includes text files with MD5 and SHA256 checksums for the final build, and another folder within it containing some previous builds): https://drive.google.com/open?id=1UiUlSbfj3agDvt-4f_YLIS0Xyuz5RtFC

Changelog:

Final release for 20211116:

Latest updates from LineageOS, including the 20211105 Android security updates.

The WiFi driver has been switched from being a kernel module to being built into the kernel. This may improve reliability for enabling and disabling WiFi and the WiFi hotspot very slightly.

The rewrite of the sepolicy containing all of the SELinux rules that I did for 18.1 has been ported over to 17.1, and so it's now of much better quality.

The audio outputted from the audio jack while playing media will now be noticeably louder, as the headset "DAC1 playback volume" for media has been increased to the maximum of 175 from 162.

An issue where there was additional extremely quiet high-pitched noise from the right speaker has been fixed.

The ZRAM size has been increased to 768MiB.

The BSP sources have been redone to closely match what has been done with the new exynos7880-specific part of Lineage's BSP sources, and with that, there are now more exynos7870-specific changes to the open source gralloc that is in use.

Some miscellaneous cleanups have been done.

The qcom_cfg.ini configuration file for WiFi has been imported from Samsung's A720SKSU5CTL2 firmware - A change within it appears to have made WiFi more reliable.

The system image size has been increased from 3072000000 bytes to 3145728000 bytes, which is the size of the system partition on Korean and Chinese variant T580s and T585s, and the smallest system partition size out of all T580s and T585s.

Some proprietary blobs have been updated as follows:

WiFi and Bluetooth firmwares from Samsung's T390XXS9CUG1 firmware

libexynoscamera3.so library from Samsung's P580ZSS1CTI1 stock firmware - This improves the situation with the issues with stretched/squashed camera previews for images and stretching/squashing in videos at some resolutions

MFC (Multi-Format Codec) firmware from Samsung's A305FDDU6CUI3 firmware

sensors.universal7870.so library from Samsung's P580ZSS1CTI1 stock firmware

As the oldest proprietary blobs are now as in Samsung's P580ZSS1CTI1 stock firmware (with a few exceptions), the vendor security patch level has been increased to 2020-09-01, which is the security patch level that firmware has.

The 32-bit wcnss_filter binary, used for Bluetooth, that was used previously has been replaced with the 64-bit wcnss_filter binary from Samsung's A520FZTU4BRB1 firmware.

Configuration files for media codecs and profiles have been updated from Samsung's T580XXS5CTK1 stock firmware.

There are many (final) updates from the (unfortunately now deprecated so no longer updated) 3.18 Android common kernel, many updates from Linux 4.4, and some updates from a few of Samsung's newer kernel sources to the kernel, and also some other various changes.

A few changes have been imported to the MMC block device driver in the kernel from Samsung's M105GDXS6CUD4 kernel sources that specifically fix extremely rare kernel panics that occurred when there was an error with a MMC device (mainly with SD cards).

Some unnecessary drivers have been disabled in the kernel.

The sdfat driver in the kernel, which is used for exFAT filesystem support, has been updated to version 2.4.5.

The fix for an issue where the duration of videos that are taken is lengthened by the time spent in deep sleep/suspended that was previously used has been replaced with a better fix in the Exynos fimc-is2 driver in the kernel.

Previous releases:

Release for 20210530:

Latest updates from LineageOS.

File-based encryption has been disabled after I left it enabled by mistake after testing FBE before moving onto LineageOS 18.1.

Release for 20210523:

Latest updates from LineageOS, including the 20210505 Android security updates.

Some changes have been imported to libbt-vendor from https://github.com/LineageOS/android_hardware_qcom_bt on branch lineage-18.1-caf (same as branch lineage-17.1-caf).

The rampatch_tlv_tf_1.1.tlv firmware for Bluetooth has been updated from Samsung's stock T585XXS6CTJ7 firmware.

There are some updates from the 3.18 Android common kernel and Linux 4.4 to the kernel.

A workaround that was used to get USB tethering and Bluetooth tethering to work is no longer used, and has been replaced with a proper fix (enabling CONFIG_NETFILTER_XT_TARGET_CT in the kernel).

Release for 20210413:

Latest updates from LineageOS, including the 20210405 Android security updates.

There are some updates from the 3.18 Android common kernel and Linux 4.4 to the kernel.

Release for 20210313:

Latest updates from LineageOS, including the 20210305 Android security updates.

There are some updates from the 3.18 Android common kernel and Linux 4.4 to the kernel, many changes to the rcu, locking and btrfs code from 4.4, and a few changes from Samsung's M105GDXU6CUA1 kernel to the kernel.

The exynos part of the BSP has a few changes from Lineage's 18.1 branch for HWC and memtrack.

Release for 20210207:

Latest updates from LineageOS, including the 20210205 Android security updates.

SELinux denials that caused the torch feature to not work have been addressed.

The issue where videos that are recorded have a duration that is lengthened by the time spent in deep sleep has been worked around - It looks like Samsung did something wrong in the camera HALs for Exynos 7870 devices.

There are some more updates from the 3.18 Android common kernel and Linux 4.4 to the kernel, and a few changes from Samsung's M105GDXU6CTL3 kernel.

Release for 20210116:

Latest updates from LineageOS, including the 20210105 Android security updates.

The custom camera provider HAL has been removed, and the camera provider HAL has been binderized - this fixes camera glitches when there is motion.

Quota support has been enabled on userdata, so that storage usage statistics can be gotten more quickly.

The Widevine DRM blobs from the Pixel 3 XL's last Android 10 firmware are now used.

The MFC (Multi Format Codec) firmware has been updated from Samsung's M105FDDU3CTK3 firmware, and the camera.vendor.universal7870.so library has been updated from Samsung's latest stock firmware (version T580XXS5CTK1).

There are some more updates from Linux v4.4 and the 3.18 Android common kernel to the kernel.

Release for 20201223:

Latest updates from LineageOS.

Address hal_graphics_composer_default SELinux denials on video_device - fixes issues with video playback with SELinux set to enforcing. (Thanks to @Kostareka for providing logs with the SELinux denials)

Release for 20201221:

Latest updates from LineageOS, including the 20201205 Android security updates.

I've prepared new BSP sources, based on Lineage's SLSI BSP sources, and the BSP libraries are now built from those sources. (Thanks to @Valera1978 for providing his old BSP sources! Without them, this wouldn't have been possible.)

Samsung's proprietary audio libraries, adapted by @Valera1978, are now used, to workaround an issue where audio will be outputted to both the 3.5mm audio jack and the speakers quietly when something is connected to the audio jack.

The build fingerprint has been changed to an older Android 8.1 fingerprint for the Google Pixel C. (For information on why we can't use the fingerprint from the stock firmware, see: https://github.com/TALUAtGitHub/android_device_samsung_gtaxlwifi/issues/1 )

Installation on the LTE variant (SM-T585, codenamed gtaxllte) is now allowed - apparently, builds for the WiFi-only variant boot and work on the LTE variant, only with no mobile networking (of course) and GPS.

There are a few minor cleanups.

Version 2 of the AOSP bluetooth audio HAL has been enabled.

FIFO UI scheduling has been enabled.

The camera libraries have been updated from Samsung's latest stock firmware, version T580XXS5CTK1.

There are a few other miscellaneous improvements.

There are some updates to the kernel from the Android 3.18 common kernel and Linux v4.4, and there are updates to some of the drivers from Samsung's M105GDXU5CTI3 kernel.

Release for 20201121:

Latest updates from LineageOS, including the 20201105 Android security updates.

The sepolicy has been improved - many unnecessary SELinux rules have been removed and a few SELinux denials have been addressed.

The init.power.rc script is now actually used to set some parameters for the interactive CPU governor to make it less aggressive.

The GNSS and sensors HAL are now compiled from source in the device tree with necessary modifications. (Thanks to @followmsi for some very useful information regarding this!)

As many vendor blobs as possible have been updated from Samsung's T580XXS5CTD1 and A520FXXUGCTI9 stock firmwares, the gpsd shim has been removed as it's no longer necessary after updating gpsd from T580XXS5CTD1 and a few unused vendor blobs have also been removed.

cbd/cpboot-daemon has been removed, because it, along with the modem_v1 driver in the kernel, no longer works with the latest bootloader and spams the kernel log with error messages, I have very little idea of what it does for the WiFi-only variant and it's unnecessary.

Made a few other miscellaneous improvements.

Many more updates to the kernel from Linux v4.4 and the 3.18 Android common kernel, some miscellaneous improvements and many changes to the f2fs filesystem driver from newer Android common kernels and mainline Linux.

The kernel is now compiled using the clang compiler after having applied the many necessary changes to it to do so.

Release for 20201022:

Latest updates from LineageOS, including the 20201005 Android security updates.

Enable config_setColorTransformAccelerated - LiveDisplay colour calibration and reading mode is now available. (Thanks to @followmsi for finding this fix.)

Add FlipFlap for flip covers. (Note that FlipFlap only works if the timeouts in Settings -> Connected devices -> Connection preferences -> Smart cover are set to 'immediately')

Fix a typo in the power profile.

More updates to the kernel from Linux v4.4 and the 3.18 Android common kernel.

Apply/backport some changes to zram and the lz4 compression algorithm from mainline Linux for faster compression and decompression, and add a backport of the zstd compression algorithm from the 4.9 Android common kernel which can be used as the compression algorithm for zram (lz4 is still the default compression algorithm).

Release for 20200915:

Latest updates from LineageOS, including the 20200905 Android security updates.

Increase microphone gains.

Many more updates from Linux v4.4 and android-3.18 and a few improvements to the kernel.

Release for 20200821:

Latest updates from LineageOS.

A few more updates from Linux v4.4 and android-3.18 and improvements to the kernel.

Revert 2 changes to the kernel related to hotplugging - should fix an issue where the device doesn't wake up after a while of deep sleeping in certain cases, and a hard reset is needed.

Release for 20200814:

Latest updates from LineageOS, including the 20200805 Android security updates.

Update the Mali graphics blob to r28p0 from r22p0.

Make a few changes for GPS that fix Assisted GPS, and switch to different XTRA servers with HTTPS.

Fix OpenCL.

Symlink libGLES_mali.so to libOpenCL.so, libOpenCL.so.1 and libOpenCL.so.1.1 instead of copying - saves a significant amount of space in /system and makes the installation zip slightly smaller.

Change media volume control to be in 25 steps rather than 15 steps.

More updates from Linux v4.4 and android-3.18 to the kernel and some improvements.

Release for 20200711:

Latest updates from LineageOS.

Android security updates from 20200705, manually applied to skip the wait for them to be merged. ('repopick -t android-10.0.0_r40')

Disable window rounded corner animations.

Reduce ZRAM size to 512MB.

Enable debug.sf.disable_backpressure.

A few more updates to the kernel from Linux v4.4 and android-3.18.

Port over/import zsmalloc, zram, zswap, zbud and zpool from Linux v4.4.

Fix the issues with hanging/freezing that were present in the previous release.

Release for 20200703:

Latest updates from LineageOS.

Enable support for using USB for MIDI.

Fix/workaround issues with USB tethering.

Remove sswap and use ZRAM.

Latest update from @Valera1978 - "update audio_policy_configuration.xml from SM-A600FN q stock"

Many more updates to the kernel from v4.4, android-3.18 and a few from v3.16.

Disable the Exynos hotplug governor again. (in the kernel)

Release for 20200608:

Latest updates from LineageOS including the 20200605 Android security updates.

Use userspace lmkd.

Enable Always On Display. (Thanks to @followmsi)

Address a few more SELinux denials.

power_profile: change names as per pie naming changes.

Switch to android.hardware.sensors@1.0-impl.samsung. (Thanks to @followmsi)

Fix freeform window moving/resizing doesn't work (In my new fork of LineageOS' android_frameworks_base repository).

Add back support for Miracast using the changes from https://review.lineageos.org/q/topic:%22ten-aosp-wfd%22 (In my new fork of LineageOS' android_frameworks_av repository).

More updates to the kernel, including many updates from Linux v4.4 and v3.16 and general updates. There are also improvements to downstream drivers.

Release for 20200512:

Latest updates from LineageOS including the 20200505 Android security updates.

Address more SELinux denials.

Remove the ro.enable_boot_charger_mode property and revert "gtaxl: workaround for offline charging".

Remove some useless services for non-existent binaries in init files.

Hide sRGB toggle in developer options.

More updates to the kernel, including many updates from Linux 4.4 and to the kernel-based wireguard implementation.

Release for 20200411:

Latest updates from LineageOS including the 20200405 Android security updates.

Update the cpu.speeds array in the power profile for 1.69GHz, 449MHz and 343MHz frequencies.

Make the power profile aware of the big.LITTLE cluster.

Address more SELinux denials and remove duplicate rules.

Use an up-to-date Samsung hardware repository based on LineageOS' repository, and make changes to the device tree for it. ((Thanks to @followmsi for changing the sepolicy to accommodate for modem/macloader having been moved to /vendor and mentioning that the Exynos hidl power HAL has to be used after the old power HAL was removed)

Enable secure ADB and set persist.sys.usb.config to none.

Use pool.ntp.org for the NTP servers.

ramdisk: cleanup the init files and fstab for readability.

ramdisk: init.samsungexynos7870.rc: only start gpsd after booting - fixes GPS when encrypted.

More updates to the kernel, including many updates from Linux 4.4, general updates (such as updates to the wireguard kernel module) and fixes.

Use sdfat for exFAT support.

Add toggle for disabling newly added USB devices.

Release for 20200309:

Latest updates including 20200305 security patches

Upgrade android.hardware.keymaster to 4.0.

lineage-gtaxlwifi_defconfig: disable CRYPTO_FIPS to get encryption partially working.

sdfat: update to version 2.3.0.

Update the BFQ IO scheduler to v8r12 using a port.

Release for 20200303:

wireless: add back Samsung's 'temporary' workaround due to qcacld-2.0 page allocation errors. Looks like this is actually necessary. Works around issues with WiFi not being possible to be enabled after some time again due to page allocation failures that still exist.

Revert duplicate "signal/ptrace: Don't leak unitialized kernel memory with PTRACE_PEEK_SIGINFO". We already had this commit as in Linux v3.18, the content of this reverted commit are useless.

Release for 20200301:

Fix a few SELinux denials. (including app_zygote denials, sepolicy in post 5 no longer needed for this build at all and also shouldn't be used anymore as more denials beyond just the app_zygote denials have been fixed)

Release for 20200229:

Initial release.

Known issues and workarounds (if any):

Issue 1: adoptable storage is reported to not work correctly.

Somewhat of a workaround to issue 1: format and use your micro SD card with the exFAT filesystem.

Issue 2: Camera previews for images to be taken at resolutions with aspect ratios other than 16:9 using the rear camera are squashed from 16:9 (while final saved images at any resolution are unaffected by any squashing), and videos taken at some resolutions are affected by similar issues with squashing in previews, and, in a smaller set of resolutions, also in final saved video files. (Note that these issues don't affect the front-facing camera)

Somewhat of a workaround to issue 2: Use resolutions at which there are no issues with squashing from 16:9.

Issue 3: the on-screen navigation bar feature that can be enabled with the option at Settings -> System -> Buttons -> "Enable on-screen nav bar" doesn't work properly.

To report issues, get a log from logcat and dmesg. If you are unsure of how to get both, there is good documentation out there for how to do so.

Sources:

A manifest containing all of the necessary repositories to make a build is in this repository on branch lineage-17.1: https://github.com/TALUAtGitHub/gtaxlwifi-manifests

Thanks to:

@Valera1978 - for all of the previous work for these devices, and for providing his old BSP sources without which the previously used open BSP sources wouldn't have been possible.

@followmsi - for fixes to various issues and other improvements, for useful information, and for working with me on much of this stuff.

LineageOS - for the Android distribution itself.

...and everyone else who's worked on anything that is in use.