[Samsung Galaxy Tab A series ROMs, Kernels, Recover] K9100ii:
This is LineageOS 18.1, which is based on Android 11, for the WiFi-only variants of the Samsung Galaxy Tab A 10.1" (2016), with model SM-T580 and codename gtaxlwifi, and the Galaxy Tab A 10.1" (2016) with S-Pen, with model SM-P580 and codename gtanotexlwifi. LineageOS doesn't need much of an introduction - It's a well-known custom firmware/Android distribution.

As was always planned, my LineageOS 18.1 builds continue on from @followmsi's LineageOS 18.1 builds that were intended for use by users. To update from his builds, my builds can simply be installed on top of an existing install from his builds without doing anything further (or "dirty flashed").

Downloads:

Note: While these builds are mainly intended to be used on the WiFi-only variants of these devices, they can be installed and used on LTE variants if you can go without mobile networking (of course), GPS and vibration.

Since I now have a T585, I've got LineageOS 19.1 builds for gtaxllte, and gtanotexllte as well, up in my 19.1 thread. I suggest using those.

For SM-T580/gtaxlwifi:

Latest build from 20221025 (with security patch level 20221005): https://drive.google.com/file/d/18PHMUSUW9A0ZfhjpSYCV0GiHW2Damskw/

Folder for builds (which contains a text file with a SHA256 checksum for the latest build, and a folder containing previous builds): https://drive.google.com/drive/folders/1wuirD9cyoguv7CQdEO5ymZ911k2ASKKD

For the T580, the latest official TWRP build from here should be used. If installing a build for the T580 to the LTE variant, with model SM-T585 and codename gtaxllte, keeping in mind some functionality will of course be missing as described in my note, the latest official TWRP build for gtaxllte from here can also be used.

For SM-P580/gtanotexlwifi:

Latest build from 20221025 (with security patch level 20221005): https://drive.google.com/file/d/11Iv75MtGAx4yvCWz-kN3wZOm-vgN4eE1/

Folder for builds (which contains a text file with a SHA256 checksum for the latest build, and a folder containing previous builds): https://drive.google.com/drive/folders/1fVGx1xGUxAtTvE0rG-OidwbXLM_93om2

For the P580, I've made unofficial TWRP builds from an updated device tree and the same kernel sources used for these LineageOS builds that must be used.

Download link for an image of my latest TWRP build: https://drive.google.com/file/d/1TAFLVpxdYQNvfvUPS_BGKx3imphR1Wd2/

Download link for a tar archive containing it for installation via Odin in the AP slot: https://drive.google.com/file/d/1Ay55ntZj7Uptzm--hiCaeG1C5lamQ1fG/

Changelogs:

Releases for 20221025:

Latest changes from LineageOS, including the 20221005 Android security updates.

The torch has been fixed.

Performance of animations and responsiveness has been improved slightly.

Configuration files for media codecs and profiles have been updated from Samsung's M105FDDS4CVG1 firmware, and audio codec support might be improved slightly (as the Codec 2.0 media codec framework has been fixed and is now used).

Some updates from the 4.9 Android common kernel have been applied to the kernel.

The WiFi drivers RX wakelock feature has been disabled - Heavy battery drain that occurred in sleep when connected to certain WiFi networks due to "qcom_rx_wakelock" wakelocks has been fixed.

Previous releases:

Releases for 20220903:

Latest changes from LineageOS, including the 20220805 Android security updates.

Some things that appeared that are only relevant for devices with mobile networking (such as the baseband version and SIM status sections in About tablet in settings) no longer appear.

The ZRAM size has been increased to 2GiB, and the swappiness is now set to 100.

A higher frequency (1246MHz, was 902MHz previously) is now set for the interactive CPU governors "hispeed_freq" value - This improves responsiveness slightly.

The sepolicy containing device-specific SELinux rules has been improved slightly.

Yet more miscellaneous cleanups have been done.

Some updates from the 4.9 Android common kernel have been applied to the kernel.

Releases for 20220803:

Latest changes from LineageOS, including the 20220705 Android security updates.

Some updates from the 4.9 Android common kernel have been applied to the kernel.

Releases for 20220628:

Latest changes from LineageOS, including the 20220605 Android security updates.

Many updates from the 4.9 Android common kernel, and some from a few other sources, have been applied to the kernel.

Releases for 20220526:

Latest changes from LineageOS, including the 20220505 Android security updates.

The problem where enabling the "Enable on-screen nav bar" option at Settings -> System -> Buttons caused touchscreen input to be disabled has been fixed.

Native support for IPsec tunnels has been enabled.

Support for Vulkan compute is now declared.

A new custom version of the open source Samsung audio HAL from Lineage's android_hardware_samsung repository is now used, rather than the stock, heavily-patched, proprietary Samsung audio HAL, with some fixes for a problem that made it unusable before where occasionally, audio would get outputted from both the speakers and the headphone jack.

The playback and low-latency capture period sizes have been reduced to 128 in the open source audio HAL, which reduces audio latency.

Pro audio support is now declared, since with the reduced period sizes, as well as with the use of the open source audio HAL, round-trip audio latency has been reduced enough for it.

Many updates from the 4.9 Android common kernel have been applied to the kernel.

Several fixes to the Sony HID driver in the 4.9 Android common kernel have been ported over to the kernel - Sony DualShock 4 controllers should now work properly.

Releases for 20220423:

Latest updates from Lineage, including the 20220405 Android security updates.

The tablet product characteristic has been added back after being mistakenly removed - Places where the device was referred to as a phone (such as the "About phone" section in settings) will now refer to it as a tablet again.

Some small improvements from my fixes for LineageOS 19.1 have been applied to the sepolicy containing the SELinux rules.

Some other miscellaneous cleanups have been done.

A few updates from the 4.9 Android common kernel and Samsung's A600FNXXU9CVB1 kernel sources have been applied to the kernel.

Releases for 20220325:

Latest updates from Lineage, including the 20220305 Android security updates.

The previously used 32-bit GPS blobs have been replaced with 64-bit blobs from Samsung's A810SKSS2CTI1 firmware.

The XTRA servers for Assisted GPS have been switched to the servers used in Samsung's stock firmwares - This fixes Assisted GPS, which turned out to actually not appear to work with the previous XTRA servers.

Even more small miscellaneous cleanups have been done.

There are some updates from the 4.9 Android common kernel to the kernel.

Releases for 20220224:

Latest updates from Lineage, including an increase of the Android security patch level to 20220205 (just an increase as interestingly, for this month, there aren't any (relevant) security updates).

The WiFi firmwares have been updated from Samsung's T395XXSDCVA1 firmware.

There are some final updates from the 4.4 Android common kernel (which is unfortunately now also discontinued along with Linux v4.4) and some updates from the 4.9 Android common kernel to the kernel.

[SM-P580/gtanotexlwifi only] Touch input and input from the back and recent apps keys is now ignored when the S-Pen is in use. (Thanks to @unknowwiiplayer for testing the changes for this)

Releases for 20220122:

Latest updates from Lineage, including the 20220105 Android security updates.

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

Some changes have been applied to a few drivers specifically for Android in the kernel (mainly the binder driver) from the 4.19 Android common kernel for Q.

A few changes from the 3.18 Android common kernel that were missing from the kernel have been applied.

Releases for 20211222:

Latest updates from Lineage, including the 20211205 Android security updates.

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

Releases for 20211114:

Latest updates from Lineage, 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 libexynoscamera3.so library has been updated 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.

The MFC (Multi-Format Codec) firmware has been updated from Samsung's A305FDDU6CUI3 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.

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

Most SELinux rules that are technically not allowed (by neverallow rules) have been replaced with much better rules or removed.

There are some (final) updates from the (unfortunately now deprecated so no longer updated) 3.18 Android common kernel, some updates from Linux 4.4, and a few updates from Samsung's J600FPUUACUH2 and A720SKSU5CUJ2 kernel sources to the kernel.

Releases for 20211023:

Latest updates from Lineage, including the 20211001 Android security updates, and a fix for the issue where the media controls in the notification panel squash the quick settings tiles and make it impossible to swipe through them when in landscape.

Workarounds for an issue with rebooting to recovery and download mode from system using the advanced restart menu or the reboot command in a shell have been replaced with a proper fix.

Yet further slight miscellaneous cleanups have been done.

[SM-P580/gtanotexlwifi only] A problem where S-Pen input wasn't registering in the right directions in orientations other than portrait, as the axes for it didn't change on orientation changes accordingly, has been fixed by enabling orientation awareness for it (Thanks to @retiredtab for sharing that fix).

[SM-P580/gtanotexlwifi only] The cursor that appeared when using the S-Pen has effectively been disabled by setting the device type for the S-Pen input to a touchscreen (Thanks to @Acatzin for the hint for this).

[SM-T580/gtaxlwifi only] 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.

[SM-P580/gtanotexlwifi only] The system image size has been decreased from 3072000000 bytes to 3045064704 bytes, to accomodate for the SM-P583s system partition which has that size. With this change, it should now be possible to install this latest build for the P580 on the P583 and for it to boot fine, since the P583 basically seems to be a P580 but for China, although I can't be certain on that.

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

Releases for 20210922:

Latest updates from Lineage, including the 20210905 Android security updates.

The ZRAM size has been increased to 768MiB.

Even further miscellaneous cleanups have been done.

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.

There are some updates from the 3.18 and 4.4 Android common kernels and Linux 4.4, a few changes backported from mainline Linux, and also a few other insignificant changes to the kernel.

An issue where there was additional extremely quiet high-pitched noise from the right speaker has been fixed. (Thanks to @Kostareka for reporting it. It likely would've gone unnoticed for at least a very long time into the future otherwise.)

First proper release for the P580.

Release for 20210810:

Latest updates from Lineage, including the 20210805 Android security updates.

This is my first build that is signed using my own release keys. This change was removed in the second build released for 20210810 (with "-R2-Test-keys" in the filename).

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 further small miscellaneous cleanups have been done.

There are some updates from the 3.18 Android common kernel and Linux 4.4 to the kernel, and a few other insignificant changes.

Release for 20210709:

Latest updates from LineageOS.

Merges of the latest changes from AOSP for repositories forked by Lineage have been picked to skip the wait for them to be merged (repopick -t android-11.0.0_r39), and the rest of the repositories not forked by Lineage were additionally switched to the android-11.0.0_r39 tag, for the 20210705 Android security updates.

A patch to the PermissionController app has been applied that adds the FAKE_PACKAGE_SIGNATURE permission group to it - The signature spoofing permission can now be managed through the permission management interface at Settings -> Privacy -> Permission manager.

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.

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

A few patches have been applied to the qcacld-2.0 WiFi driver in the kernel, which are mainly vulnerability fixes.

Release for 20210617:

Latest updates from LineageOS, including the 20210605 Android security updates.

The WiFi and Bluetooth firmwares have been updated from Samsung's A720SKSU5CTL2 firmware.

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

The health HAL has been upgraded to version 2.1.

There are a few other small miscellaneous changes (mostly small cleanups).

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

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.

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

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.

Release for 20210508:

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

New SELinux denials with Android 11 have been addressed, and with that, SELinux is now set to enforcing by default, and the sepolicy, which contains the SELinux rules, has been rewritten almost entirely, and is now of much better quality.

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

BPF offloading for tethering has been disabled.

The audio HAL has been upgraded to version 6.0.

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.

Some tcp_info-related patches have been applied to the kernel, and with that, a workaround, a patch titled "TcpSocketTracker: Opt-out for TCP info parsing on legacy kernels", is no longer used since it's no longer necessary.

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 20210407 (My initial 18.1 build. This changelog continues on from @followmsi's last 18.1 build that was intended for use by users):

Latest changes from LineageOS. The crashes that occurred when setting a new wallpaper that were discussed earlier in this thread appear to have been fixed.

Merges of the latest changes from AOSP, including the 20210405 security updates, have been picked to skip the wait for them to be merged. (repopick -t android-11.0.0_r34)

The same workaround that was used on 17.1 to get USB tethering and Bluetooth internet access sharing to work has been forward-ported and applied.

vintf manifest override enforcement is now enabled.

The vendor/lib[64]/egl/libGLES_mali.so blobs are now symlinked to vendor/lib[64]/vulkan.exynos5.so, rather than copied to vendor/lib[64]/hw/vulkan.exynos5.so - This is a proper fix for Vulkan support.

RSA key verification for ADB is enabled again, and ADB isn't enabled by default and on boot anymore.

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

Known issues and workarounds (if any):

Issue 1: Occasionally, when trying to select quick settings tiles in the notification panel, it will crash to the lockscreen.

I have no idea about this issue. It seems like some type of generic systemui crashes. But regardless, it doesn't exist under Android 12 which I've moved onto, and it's here to stay for 11 unfortunately.

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.

To report further issues, get a log from logcat and dmesg. If you're unsure on how to get either, there's good documentation out there for how to do so.

Sources:

A manifest containing all of the necessary repositories to make a build for either the T580 or P580 is in this repository on branch lineage-18.1: https://github.com/TALUAtGitHub/gtaxlwifi-manifests

Thanks to:

@Valera1978 - for all of the previous work for the T580 (and T585) long ago, 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.

Anyone who has previously tested anything new I've put up for testing, reported results, and gave details for me to get it working if it was necessary.

The Lineage team - for the Android distribution itself.

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