[Samsung Galaxy Tab A series Questions & Answers] jedld:
I've just got a new Samsung Galaxy TAB A 7.0 LTE SM-T285, For some reason I can't seem to find any resources for this hardware yet in this forum, anyone know where I could find one? I'll try to find out if the current methods (custom recovery and root) for other tab versions work on this.

CUSTOM ROMS

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Android 5.1.1 Lollipop (Stock)

Tinker V5 Edition based on the Samsung Stock Rom SM-T280/T285

Android 6.0 Marshmallow

Cyanogenmod 13 for the SM-T285 Only

OMNIRom for the SM-T285 Only

Android 7.1 Nougat

Cyanogenmod 14.1 for the SM-T285 Only (Experimental, things are broken, depcrated in favor of LOS 14.1)

LineageOS 14.1 for the SM-T285 Only

Other Operating systems

Porting for Sailfish OS is currently in progress for the SM-T285, stay tuned

TWRP RECOVERY AND ROOT

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TWRP is available for both the T280 and T285. You should find the relevant threads in this Galaxy Tab A forum.

If you want to root stock, easiest way is to install TWRP and go for SuperSU. Please see the TWRP threads for SM-T280/T285 on how to root after TWRP is installed.

KERNEL

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Custom kernel with working sources for the SM-T285 can be found Here

DEVELOPMENT

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If you want to build LineageOS 14.1 on your SM-T285 LTE device, you can use this manifest, not that this is still a work in progress:

https://github.com/jedld/android.git

UPDATE 10/06/2016

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After a couple of weeks of trial and error and tinkering, I've been able to compile a kernel for the SM-T285 from source and so far it seems to work flawlessly!

Screenshot here: http://imgur.com/a/HRgsq

link to my kernel sources here: https://github.com/jedld/kernel_samsung_gtexslte.git

You can also thank samsung for giving us a "broken by default" kernel source. I had to mix and match defconfigs from their other kernel releases just to make this thing work. Download modified boot.img here:

http://xdaforums.com/galaxy-tab-a/development/kernel-galaxy-tab-7-0-2016-lte-sm-t285-t3474967

UPDATE 09/20/2016

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This device is now ROOTED!

http://xdaforums.com/galaxy-tab-a/help/resources-samsung-galaxy-tab-7-0-2016-t3431022/post68777842#post68777842

Download Pre-rooted Tinker Edition V5 in this thread: Tinker Edition Thread

Post Root Post Mortem Analysis for the SM-T285 (09/21/2016)

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Q: How were you able to find root? What did you do?

A: Surprisingly the SM-T285 bootloader isn't actually locked like we thought it was (Once you OEM unlock of course and disable FRP). The bottomline is that

we simply needed patches to mkbootimg to properly package a boot image for this device as there were additional fields and sections not found on a normal boot image. There were even minor breaking difference between the tab 4 and the boot image for this device.

Q: I thought the bootloader was locked?? Why did it take so long?

A: I blame it on the really vague errors the bootloader shows when loading an improperly packaged boot image. What helped was my faith to open up a hex editor when I needed to, and really look at the stock images and the images we were making. What really pushed me to investigate further was the fact that I was able to make a really small modification to the ramdisk and use the abootimg -u update function instead of the create options.

Q: So the bootloader doesn't really check the image?

A: Yup, The bootloader doesn't do any check. I haven't checked if that is the case for the recovery partition though. Even without the SELINUXENFORCE headers at the end it still continues like other samsung devices do.

Q: So the mkbootimg patches are all that we need?

A: Yup, if you have CM, AOSP build env ready you can simply add the modified mkbootimg to system/core:

https://github.com/jedld/degas-mkbootimg/commit/b63ae38e2ab7040cc7ddaef777652a56b2e48322

Sample usage below:

degas-mkbootimg -o boot.img --base 0 --pagesize 2048 \
--kernel boot.img-zImage --cmdline "console=ttyS1,115200n8" --ramdisk boot_kitchen/boot.img-ramdisk-new.gz --dt boot.img-dt

Next challenge will be getting Cyanogenmod on this device as well as TWRP.