Galaxy Tab S 8.4 (T700 / T705 Exynos5420) Discussion

Help and support for SM-T700 / SM-T705 Exynos5420 should be discussed here.


40 thoughts on “Galaxy Tab S 8.4 (T700 / T705 Exynos5420) Discussion

  1. [KERNEL] [SM-T700 / T705 Exynos 5420] SkyHigh Kernel-MM [2017-01-25]

    [Custom GCC 6.3.1 20161224 (Graphite optimizations) + Synapse + Aroma]


    – Modified from the LATEST SM-T705 official Samsung source: Samsung OSRC
    – Ramdisk base: T700XXU1CPJ2 T705XXU1CPI4
    AUTO-ROOT SYSTEM-LESS SR3-SuperSU-v2.79 (on flash)
    – SELinux PERMISSIVE (default) or ENFORCING
    AROMA Installer (set your own defaults)
    – Auto-Install busybox v1.24.1-Dorimanx & Sqlite3 to /system/xbin (on flash)
    – Compiled with Custom GCC 6.3.1 20161224 + Graphite optimizations
    – Linux 3.4.113-EOL
    – init.d script support (drop in script & set permissions to 755 or 777 and reboot)
    – adb insecure
    – Secure storage = false (should prevent WIFI settings & passwords wiping on reboots)
    – Reduced logging
    – CD_ROM emulation (DriveDroid) support
    – exFAT FS support
    – NTFS R/W (Paragon) support
    – CIFS support (not tested)
    – NFS support (not tested)
    – ISO 9660 CDROM & UDF FS support (not tested)
    – mount all partitions NOATIME (better performance & efficiency)
    – Dynamic : Fsync, Read-Ahead, Dirty Page Writebacks
    – Adaptive : Dirty Ratio, Dirty Background Ratio, VFS Cache Pressure
    – PowerSuspend driver
    – QuickWakeUp driver
    – Microsoft X-BOX gamepad controller module (updated)
    – Slub tweaked
    A tonne more select patches for features, better optimization (performance & efficiency). I don’t use a “shot-gun” approach you see in man other kernels. They won’t even hit the side of a barn !!
    Synapse app UCI support for many kernel configurations + much much more !!


    – About
    – CPU
    – CPU voltage control
    – CPU governor
    – GPU
    – GPU voltage control
    – Devfreq (memory / internal)
    – Thermal
    – IO
    – Memory
    – Advanced
    – Power Suspend
    – Doze
    – Wakelocks
    – Audio
    – Battery
    – Screen
    – Network
    – Security
    – FS (file system)
    – CortexBrain
    – Crontab
    – USB mode
    – Modules
    – Backup & Restore profiles + EFS (auto on boot to /sdcard/SkyHigh/EFS)
    – Logs
    – Reboot
    – Info


    – My family !!
    – Chainfire – root & SuperSU app
    – AndreiLux – years of support for Exynos development and his various kernel features + Synapse app and UCI code
    – halaszk – patches and some Synapse code I adapted to many of my kernels
    – dorimanx – BusyBox and various ramdisk tweaks/ideas
    – apb_axel – I adapted and used many of the Synapse controls to suit earlier kernels
    – YashdSaraf – BusyBox-Cleaner script
    – Android File Host
    – Linus Torvalds & Linux Foundation
    – Google & Samsung OSRC
    – and many others!
    – All those in my select private group that have provided constructive feedback, help, and support.


    Does dumb-ass (aka KennyG123) actually comprehend what “off-site” means? Fuck no !!

    Galaxy Tab S 8.4



    1. Still a tonne of stuff to do. Some thing I like not working yet. But this is much better and “cleaner” than earlier builds. Suppose it’s only been 1.5 years ! πŸ˜† I haven’t tested LTE either, I don’t use a SIM.


    1. I’m sorry, I only have a T705 exynos5420 and only intend to share my personal build for that. This device is just way too old to invest further support, since I already support 17x other device variants. I am not ‘robot’ πŸ˜‰

      BTW,………. this is a KERNEL


  2. Need to tidy up tomorrow. Will share after then, maybe next day? Not sure. Have not tested everything, and one feature needs fixing in Synapse. Might leave it for another time and just temp disable it from page layout. Made a few commits and optimizations today, so also need to give things a whirl !!


  3. This sounds nice. I’ve been using your kernel on my T700, when you were still using XDA as place to share your projects. It’s not like I’m rushing to use a custom kernel, I don’t have enough knowledge to use it to its full potential..Still I’m fascinated by your work and would be cool to test it. So in case you would ever think about releasing it,here’s a tester :p .
    Well done anyway, our tablets still run strong


      1. Yea,I read your first post and I was referring to the fact there would have been a very small chance you had released it for other variants. :p


  4. Okay, I’ll try give support to the SM-T700 Exynos5420 variant. Uses exactly same drivers (minus) modem and some sensor changes etc. The source will always be based on T705 though, I’ll just use variant specific ramdisks. If you have issues, afraid that will be just “tuff luck”. Getting real close to first public share. Having major PC corruption and boot issues. I think it’s on its way out.


  5. Well. I’m actually ready to build, and with just one feature that’s not working. BUT. PC is dying…… Managed to save my work, but unable to boot or complie. Once in a while I’m able to boot, but the HDD makes ticking noises. Huge slowdown and read errors. Loads of corruption. Think the issue is caused from hardware > OS corruption…. hopefully get it booted again to complete the builds


  6. Finally managed to build for both SM-T700 / SM-T705 variants. For use with STOCK TW based firmwares. Please ensure you delete any ROM cook bullshit “tweaking” from various places ie. init.d build.prop and remove any other kernel or CPU control apps !!

    Will update the very first post when I am able. Currently having major PC issues…..

    Linaro 6.2.1 + Linux 3.4.113 + many selective optimizations + Synapse + Aroma


  7. Just got PC back up and running. Had to go buy a new HDD and setup everything from scratch.

    Anyway. there are a few Synapse BUGS to sort out.

    1 – enabling cortex-brain will cause lock with “sed” and freeze Synapse and causing CPU stuck at max. Please do not enable this. If you have, then please force close it and wipe Synapse data. then reboot !

    2- Crontab is not working


  8. Well, some more good news. I’ve managed to fix cortexbrain + crontab + merged new source !! A little time to test overnight, and I’ll test again tomorrow with updated ramdisk for T705 πŸ™‚

    Need some rest after frigging with the PC all day. I expect the tests to have no issues, so expect to update tomorrow night.

    Then I can get back to my Note 5 πŸ˜‰


  9. Didn’t test crontab but noticed the cortex issue. Nice to hear you’ve already fixed it. Couldn’t play with settings today but seems everything is working flawlessly on my t700.1 question though, are the tweaks in the cortex tab affected by the cortex master switch itself or do they work on their own? Anyway as always, nice work!


  10. I’m really happy seeing the far best kernel and developer supporting the Tab S family one more time πŸ™‚
    Even that unfortunately i cant test it because i have a T800, I’m very happy about it!

    I still on TW 5.0.2 for one simple reason, i love your kernel. Realiabre, feature rich and make my tab s fly πŸ˜‰

    Best wishes for you, hope you keep the great work, and good luck with your pc!

    Liked by 1 person

    1. This MM kernel has less Synapse “features”, but what I have implemented is hand-picked patches and much much refined in every single department.

      Who knows, never know. I’m back onto my Note5 for now.


    1. Just a couple things I found in Synapse to take care of. Noticed when I diff some scripts between my 7420 and 5420 scripts. Nothing “serious” to worry about. But I’ll still sort it out….. eventually.


  11. somehow the latest version of this kernel bootloop in the latest T705 stock firmware to the point unable to enter TWRP…

    boot to recovery: samsung splash > TWRP splash > REPEAT….
    boot to system: samsung splash > samsung animated > REPEAT… never goes into home…

    steps to repro: flash latest stock fw (T705DDU1CPL3) > first boot > flash TWRP > boot to TWRP > flash SkyHigh MM 2017-01-25 > clear dalvik > boot to system > BOOTLOOP…

    steps to recover: FLASH FULL FW VIA ODIN….

    it even corrupted my adopted sdcard……

    any fix for this? I really wanna use this awesome kernel….

    Thanks so much…..


    1. Perhaps you were previously rooted and or with another root method. This is all really easy…..

      1. Flash stock firmware
      2. Flash TWRP
      3. Flash kernel
      4. No need to wipe anything. Just reboot system…

      More than likely something left on your data partition that cause issue, but a previously modified system also. Definitely not the kernel. How on else did I flash it…. same as state above.

      User responsible to backup their own data and common sense dictates copy it off device.

      If the above doesn’t work. Then full wipe system, data, dalvik-ART and flash full stock as described above. Will sure be fine.

      And don’t forget to BACKUP !!


    1. I’ll only be using it with whatever Thai firmware is released. There is a tonne more to do on kernel and ramdisk and synapse, as well as build script. There is no more “development” except for compatibility with my own firmware. I don’t build for XDA. They are just ungrateful “children”. If rather let SkyHigh become a has been. Same I’m stopping Exynos7420 development and not gonna publish my latest update. I’d rather no one have it than let those theiving shit-stain Tkg “super stealing” kernel rip my copyright material, remove legal licence, republish and modify and without permission of the original author == me ! But hey, he does have a “recognised PoS” tittle for “his” efforts and contributions


    1. There is no Headphone volume control, just speaker volume control ……. so why would it work when there is no control? However, you may adjust headphone equaliser band gains, and that definitely works. If it doesn’t on yours, you have messed up your stock ROM.


      1. Sorry my mistake it was earpiece .
        If your planning for next update that if possible to add RGB color control in screen section (RGB,SATURATION, HUE,CONTRAST, COLOR TEMPERATURE OR GAMMA)
        and headphone volume gain or hd audio codec.


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