yashsingh1/xdaforums huggingface dataset:
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
THANK YOUUUUUUUU !!!!!!!!!!!

tetakpatalked from my N7100
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
I'll confirm later, I'll take a rest for 1 or 2 hours first :D Please confirm if this new released boot your device.

Since you experienced dual boot on different device, what's your opinion about NEXT solution, including patched PhilZ Touch? Better over PM ;)
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
Yes, it boots wonderful :D LOL, I was flashing during your answer. Screenshot attached. Get some sleep, you really deserve it! I will try to migrate to f2fs today and see if fails, SlimBean is much smaller than any KK rom.

EDIT: It seems that there is just a little bug: the OS can't access the /sdcard1 now. Could it be for FAT32 formatting? The card is OK, all data are there and accessible in recovery. I will try with older blobs and report back until you wake up.

EDIT 2: OK, I have tested now what causes the extSDcard mount problem, it is kernel related. Tests and logs:

the new 2.1.8 kernel first with latest proprietary-vendor-samsung.zip (attached above) and after that with the old ones since last year. Yet, it makes no difference, extSDcard doesn't get mounted. Both dmesg 2.1.8 and logcat 2.1.8 attached are done with the newest blobs. IDK if you've changed something, therefore I say "new" and "old". The logcat is probably useless, while creating it I was trying to access extSDcard first in the Root Browser, then under settings/storage/ tried to mount it (greyed out)

dmesg 2.1.5 is done with the blackhawk 2.1.5 kernel and the "new" blobs, all works perfectly fine there

I hope that my dmesgs will be helpful for debugging :)

Honestly, I am really grateful to you for this accidental little bug, I finally backuped my whole extSDcard to my PC, I have 12GB of important data on it :D

tetakpatalked from my P5110
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
[MENTION=4021423]ketut.kumajaya[/MENTION] GREAT NEWS, my migration to F2FS with the new 2.1.8 kernel is PERFECT!

This is the very first time it works on my P5110! Thank you so much!!

I notuce slight increase in the speed of my UI, less than I've hoped to get, yet this is also the best Antutu score I've ever reached, I think my Tab has never made it yet above 12K.

P.S. yes, I do OC, always to 1.42 GHz, rock stable here- strangely, but Antutu displays 1.52 GHz ???

Amazing, Ketut, only the access to sdcard1 from OS is missing and I will can say "absolutely perfect work" then! :)

This was my workflow for successful MIGRATION TO F2FS on the P5110, whoever interested:

my ROM used: SlimBean (4.3.1), flashed today's release of blackhawk 2.1.8 kernel with compatible blobs (proprietary-vendor-samsung.zip) without any wipes

in OS: did backup of all my data from the internal storage that I care for (moved to external SD card)

used PhilZ touch recovery blackhawk F2FS version 6.25.0 for the migration to f2fs

under "Backup and Restore" created "custom backup job to /sdcard1" of: system, data and data/media

formatting to F2FS done under "Mounts and Storage" in this order (prompt for ext4/f2fs will always come):

/system

/cache

/data and /data/media (/sdcard)

restored my freshly done nandroid backup under "restore from /sdcard1"

rebooted into Android, now as F2FS

Here are the screenshots:

tetakpatalked from my P5110
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
Great :good: Just found an issue in my patched PhilZ Touch in combination with NEXT dual boot tool. Without a journal, system.img initially not detected as ext4 filesystem by blkid, so no option to format it as ext4 or f2fs. I have changed NEXT tool, we can recreate system.img without loosing user data but found this bug when trying to restore /system nandroid backup, already fixed it. I also found f2fs journal consume a lot of space, I will check it later. I will upload updated NEXT tool, I'm sure [MENTION=5153662]Android-Andi[/MENTION] will merge it to the next PhilZ Touch build. Have no idea about external SD card bug, but I'll check it for sure.
[Galaxy Tab 2 10.1" Android Development] Android-Andi:
[MENTION=4021423]ketut.kumajaya[/MENTION] you can send me the new NEXT tool, i can rebuild PhilZ Touch Blackhawk-F2FS later this evening.
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
Just uploaded it to Dev-Host blackhawk-next-tool-0.2-p31xx-p51xx.zip, user can directly use it as a flashable zip. For PhilZ Touch, remove update-binary inside and name it as tool.zip, you know the rest :)
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
As you can see from the attached screenshot to my previous post, I had no problems to format /system to f2fs, also restore of a custom job nandroid backup didn't revert it back to ext4. Although, ATM I didn't use the DB tool.

I have used your PhilZ touch 6.25.0-f2fs compiled for the P5110 by [MENTION=5153662]Android-Andi[/MENTION]. The recovery recognizes extSDcard and can flash from it. The OS doesn't, also PC can't see it when connected to the Tab with USB cable.

Your old 2.1.5 kernel works perfectly fine with the very same proprietary-vendor-samsung zip file. Therefore I have attached both dmesg files, for easier comparement (and hopefully easy & fast debugging)

Thanks for all your amazing work and thanks in forward for the debugging time.

tetakpatalked from my P5110
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
[MENTION=5051515]tetakpatak[/MENTION] Just found the source of SD card access problem:

dmesg:

<3>[ 6.230163] C0 [ vold] fs_mgr: Cannot open file /fstab.espresso10

logcat:

I/Vold ( 698): Vold 2.1 (the revenge) firing up

E/Vold ( 698): failed to open /fstab.espresso10

E/Vold ( 698): Error reading configuration (No such file or directory)... continuing anyways
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
[MENTION=4021423]ketut.kumajaya[/MENTION] Thank you so much!!

Just as a very little sign for a greatest respect for all your hard work and spending part of your time with us here instead of only with your beloved ones..... really highly appreciated!

Transaction code 4J007408C3792672G
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
[MENTION=5051515]tetakpatak[/MENTION]

UPDATE:

NEXT 2.1.8.1: PAC KitKat support, P51xx SD card access bug fix

http://xdaforums.com/showpost.php?p=51678873&postcount=472
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
Ketut, you are a genious!!!!!!

Works just PERFECT! You can release it as "stable" :D extSDcard is perfectly accessible now!!!!

tetakpatalked from my P5110
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
Good night! Morning here exactly :laugh:
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
Good night dear Ketut. Thanks for amazing work today :victory: :good:

Just for your control if needed for anything, I attach dmesg and logcat from (as much I can see) flawless working SlimBean / kernel blackhawk 2.1.8.1 / P5110 / as F2FS.
[Galaxy Tab 2 10.1" Android Development] doc-oc:
So, 5110, stock firmware 4.1.2 France, TWRP-recovery, 2.1.8.1 kernel version - everything works fine: no spontaneous reboots, extSdCard feels good, any application work correctly. Max frequency for this kernel version is 1420. If the processor speed is 1480 , then when tested in Antutu it drops to 800. The CPU frequency is monitored using a CoolTool.

Antutu results:

1. Stock kernel - 8820

2. 2.1.8.1 blackhawk kernel by default - 8856

3. 2.1.8.1, CPU - 1480 MHz/sio, GPU - 512 MHz/activeidle - 9435

4. 2.1.8.1, CPU - 1420 MHz/sio, GPU - 512 MHz/activeidle - 11058

I would like to test F2FS, but can't find Philz touch blackhawks F2FS recovery version.
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
[MENTION=5304521]doc-oc[/MENTION] better use STweaks by Gokhan Moral from Play Store

tetakpatalked from my N7100
[Galaxy Tab 2 10.1" Android Development] Android-Andi:
[MENTION=5304521]doc-oc[/MENTION] ---> http://xdaforums.com/showpost.php?p=51694355&postcount=180 :) PhilZ-Touch in all variations :D
[Galaxy Tab 2 10.1" Android Development] doc-oc:
Yes, of course I use STweaks from GP for kernel management ;)

CoolTool - it is only widget for system monitoring.
[Galaxy Tab 2 10.1" Android Development] doc-oc:
I don't know why, system now is more lagging. I will try to back to the ext4 file system for cheking.

No, false alarm. Just a little time has passed from the system recovery. The interface is now faster and smoother.

Confirm - memory card detected and working properly.

Yes, F2FS works!

Antutu I/o database stock - 485

-------------------- ext4 - 530-600

-------------------- F2FS - 560 (no overclocking)
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
Dear P51xx owner, for ease of maintenance, for the first time NEXT kernel 2.1.8 for P51xx use P31xx's ramdisk. NEXT kernel's ramdisk complexity making it's hard to maintain a different ramdisk for different target. About external SD card not accessible bug, it's because I forgot about vold configuration integration to fstab since 10.2. Simple fix for this bug: softlink fstab.espresso10 to fstab.espresso on boot :D
[Galaxy Tab 2 10.1" Android Development] doc-oc:
My new Antutu scores :)
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
LOL don't exeggarate :D we all here just love when things work fine and try to debug all that doesn't. There we do what we can. But indeed Ketut really rocks, he is amazing.... BTW, don't you use Tapatalk? Great for forum following....and no limit for "thanks" :D

Did you try f2fs?

tetakpatalked from my N7100
[Galaxy Tab 2 10.1" Android Development] CSP III:
Ha, I do use is and I am on it now. Forgot about the no limit thanks thing. No exaggeration on my part friend. I just want to be sure that the appropriate people know how grateful I am. Sadly, I forgot to mention Tux in there though. All apologies. A bit gunshy on f2fs, but I am going to go for it with your work about. Thanks for not forgetting:thumbup:
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
[MENTION=5061733]CSP III[/MENTION] if I remember well, tuxafgmur has written that he attends to add f2fs support to his next version.

I have used Ketut's 2.1.5 kernel long time with CM10.x and admired it. Now when he has finally has compiled a kernel for our P51xx with f2fs and for KK roms, this is a X'mas time for us! That is something to use for long time.

AA has ported us so many great ROMs, our device makes really fun now.

tetakpatalked from my N7100
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
UPDATE: 8/4/2014

NEXT 2.1.8.2:

Omni ROM Samsung dock keyboard workaround, build the driver as module. Not loaded by default. For Samsung keyboard dock owner, you can use STweak to load this module on boot

Omni ROM for P5113 RCP input fix. SII9234 RCP input device only be registered as long as MHL is connected, adapted from tuna kernel

Total 8 commits, I'll tell you later but please try this kernel and help me to solve battery drain issue on KitKat as reported by Android-Andi and Viskesh. Only 2 commits possibly related to this issue actually

http://xdaforums.com/showpost.php?p=51678873&postcount=472
[Galaxy Tab 2 10.1" Android Development] elcocolo50:
Hi ketut the hardware keyboard problem is gone. Thanks very much
[Galaxy Tab 2 10.1" Android Development] elcocolo50:
Hi this is my antutu benchmark with the new kernel update.
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
UPDATE: 10/4/2014

NEXT 2.1.8.3:

WiFi driver incremental update

http://xdaforums.com/showpost.php?p=51678873&postcount=472
[Galaxy Tab 2 10.1" Android Development] ron12:
I'm trying out this kernel, am quite please with the performance on my P5113. AnTuTu score of 11408 running at 1350MHz. :D

Oddly, running OC'd at any higher speed than 1350MHz causes random FCs of various apps, including AnTuTu. Even more odd is when AnTuTu does run to completion, the score is very low, around 8,500 when OC at 1420MHz, and drops under 8,000 at 1520MHz.
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
It's normal. If your CPU become too hot, the onboard Smartreflex driver (kernel independent) throttling your CPU to the lower frequency to protect your CPU.
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
I have used the 2.1.5 kernel with SlimBean 4.3 with OC 1,42 without any problems ever. CPU cool even be games and Antutu score 14.000 (P5110)

Ketut, you simply rock, you are our Kernel King Developer for the Tab 2. And the idea of two parts is also great (prioprietary-vendor), very original.

tetakpatalked from Nexus 7
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
Thanks to gokhanmoral, based on his idea, my kernel simply work on almost all ROM. Run 2nd ROM in a boot box and utilized AROMA boot menu still my original idea but no single reason to ignore base rule developed by him. Thanks to cmenard, with his traceable github commits, I managed to bring overclocked kernel to JellyBean. Thanks to jiangyi to keep the authorship of the ducati change. Thanks to CodyF86 to keep the authorship of kernel upgrade. Thanks to codeworkx, a big developer like him mark my name to his github change. Thanks to the spirit of openness of open source projects. Thanks to this community for calling me back here since my daughter doesn't care about ROM and kernel but games :laugh: Thanks to my donators, every single penny is a special ;)

EDIT:

History behind this kernel, to refresh our memory and reference for a new user:

http://xdaforums.com/showthread.php?t=1855700 - the first kernel utilized omapzoom.org's GPU driver, earlier than CM :D

http://xdaforums.com/showthread.php?t=1859227 - why different proprietary vendor needed

http://xdaforums.com/showthread.php?t=2248664 - boot multi ROM
[Galaxy Tab 2 10.1" Android Development] CSP III:
Right on K.K. And many thanks to you as well. Let us not forget that. Love open-source. Wish the world was as open as this. Good day to you!!!!
[Galaxy Tab 2 10.1" Android Development] doc-oc:
Hello. I cannot understand - are ZRAM and SWAP work on F2FS file system, or not? I can not install any application verifying the zram from GP, for example.
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
I built 2.1.9 6 days ago:

blackhawk-next-kernel-2.1.9-p51xx.zip

proprietary-vendor-samsung-update.zip

Changelog:

https://github.com/kumajaya/android_kernel_samsung_espresso10/commits/cm-11.0

Please try and report back :good:
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
As you know, this kernel works on a lot of ROM from 4.1.x to 4.4.x. Please tell me your ROM version. In sync to CM 11.0, for CM 11.0, this kernel have no swap/zram helper anymore.
[Galaxy Tab 2 10.1" Android Development] doc-oc:
Samsung official firmware 4.1.2 (France), F2FS: system, cache, data, data/media. Latest Philz Touch recovery by Android-Andi, next-kernel 2.1.8.1.

I had previously tried to activate swap and through the terminal, as in the instructions for a kk-boot kernel , and using third-party applications. But in the first case, the partition is not created (df command in teminale for verification), and in the second case "unsupported kernel".

How I can check and set seam - I don't now.
[Galaxy Tab 2 10.1" Android Development] elcocolo50:
Hi ketut I flash the new kernel and all run smoth and fast this is my new antutu benchmark.Thanks you for you job.
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
Sorry, swap and zram support disabled since 2.0 :D Please check complete changelog from http://xdaforums.com/showthread.php?t=2285366 post #2.
[Galaxy Tab 2 10.1" Android Development] doc-oc:
Oh, thanks for the answer. I read mostly just changelogs for 5100, and therefore missed this moment. To be honest, for me this question is purely academic interest, because I am quite satisfied how my tablet work after your kernel flashing.
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
I've lost my interest to swap and zram. In long period of usage, I feel it's slow down my device.
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
Hey, Ketut +1

What for, when you brought us f2fs :D

BTW, I haven't even tought of it, but 2.1.9 also has full f2fs support, true?

tetakpatalked from the legendary i9000
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
Yes, of course.
[Galaxy Tab 2 10.1" Android Development] doc-oc:
Hello, Ketut. Will you make proprietary-vendor-samsung-update for 4.1.2 stock rom? I flashed new 2.1.9 kernel and proprietary-vendor-samsung-update.zip on my 4.1.2 full stock rom - camera, autorotation and other didn't work. After I've reflashed only proprietary-vendor-samsung-4.1.x.zip and everything is working now.
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
You gave an answer to yourself already.

Flashing proper blobs is important here.

You have flashed wrong ones at first.

The blobs for 4.1.x ROMs need no update as they do perfectly well what they should.

tetakpatalked from N7100
[Galaxy Tab 2 10.1" Android Development] doc-oc:
All is not well in the Danish kingdom. If the logo with the words "Samsung" located at the bottom, then there are freezes and lags while scrolling desktops. Previously such freezes observed while the logo was located at the top - it is normal. If the tablet is in a position where the logo is located on the top, then there is some strange animation while scrolling desktops and lite freezes. In this position, it is not convenient to press the control buttons. That's why I was asking about the update. Now I'm back to version 2.1.8.3
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
[MENTION=5304521]doc-oc[/MENTION] on my tab, all the stock ROMs were really laggy. Maybe they work better on some other tabs.

Did you try 2.1.5 kernel version? Give it a try, I am courious. It was Ketut's masterpiece of one year ago. It just doesn't have KitKat support, AMAIK

tetakpatalked from N7100
[Galaxy Tab 2 10.1" Android Development] doc-oc:
Yes, I did try 2.1.5, but the best ever kernel is 2.1.8 + F2FS file system - my tab is very! smoothly and fast (as for stock rom, of course ;))
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
Please check post #1 and #2.
[Galaxy Tab 2 10.1" Android Development] doc-oc:
So, new blackhawk-next-kernel-2.2 works correctly with proprietary-vendor-samsung-4.1.x.zip on my stock 4.1.2 rom - everything is smoothly, fast and all functions work good.
[Galaxy Tab 2 10.1" Android Development] lvdoan:
[MENTION=4021423]ketut.kumajaya[/MENTION]

I wonder whether your kernel works with SlimKat 4.4

My device GT-P5100
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
http://xdaforums.com/showpost.php?p=52168045&postcount=307
[Galaxy Tab 2 10.1" Android Development] lvdoan:
Thank you, Ketut. Very happy to hear that your NEXT kernel also supports dual boot for SlimKat. As this will be the first time I install DB. Below is what I'm going to do and I don't want to brick my device. Just correct me if I'm going wrong.

Thank you.

My current facts:

- Device: GT-P5100

- ROM: SlimKat 4.6 weekly

- Kernel: Stock SlimKat

- Recovery: TWRP 2.7.01 Android-Andi

- Have Samsung stock 4.1.2 nandroid backup by CMW 6.0.2.7

And I want Slimkat 4.6 as 1st ROM:

1. Reboot into TWRP recovery and flash blackhawk's NEXT kernel (blackhawk-next-kernel-2.2-p51xx.zip)

2. Flash "proprietary-vendor-samsung-4.1.x.zip"

3. Update TWRP recovery to the latest PhilZ Touch - blackhawk repack version - recovery (philz_touch_5.05.0-p5100-blackhawk.zip) (I don't know if "GT-P5100_PhilZ-Touch-Recovery_6.26.1-blackhawk.zip" is OK?)

4. Reboot into secondary recovery and choose "Secondary Recovery"

5. Restore Samsung stock 4.1.2 nandroid backup (I'm not sure it can be restored from CMW 6.0.0.27 backup. If not, how can I install Samsung stock ROM at this step, by ODIN?)

6. Reflash blackhawk's NEXT kernel and "proprietary-vendor-samsung-4.1.x.zip"

7. Reboot
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
And I want Slimkat 4.6 as 1st ROM:

1. Reboot into TWRP recovery and flash blackhawk's NEXT kernel (blackhawk-next-kernel-2.2-p51xx.zip)

2. Flash "proprietary-vendor-samsung-4.1.x.zipproprietary-vendor-samsung-update.zip"

3. Update TWRP recovery to the latest PhilZ Touch - blackhawk repack version - recovery (philz_touch_5.05.0-p5100-blackhawk.zip) (I don't know if "GT-P5100_PhilZ-Touch-Recovery_6.26.1-blackhawk.zip" is OK?)

4. Reboot into primary recovery, create system.img for stock ROM using Dual Boot Tool from recovery Advanced menu

5. Reboot into secondary recovery and choose "Secondary Recovery"

6. Restore Samsung stock 4.1.2 nandroid backup (I'm not sure it can be restored from CMW 6.0.0.27 backup. If not, how can I install Samsung stock ROM at this step, by ODIN?) ketut.kumajaya: Odin override your recovery, kernel, and 1st ROM

7. Reflash blackhawk's NEXT kernel and "proprietary-vendor-samsung-4.1.x.zip"

8. Reboot
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
Dear [MENTION=4021423]ketut.kumajaya[/MENTION], you probably know it already but I just wanted to confirm that your new updated proprietary vendor samsung binaries work just flawless on Slim 4.3 and Slim 4.4 ROMs. I have tested with the 2.1.9 kernel

tetakpatalked from P5110
[Galaxy Tab 2 10.1" Android Development] lvdoan:
Thank you, Ketut. I did it. Will report if there's any issue.
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
On 3G device, stock 4.2.2, incompatible WiFi firmware will result WiFi tethering fail to start.
[Galaxy Tab 2 10.1" Android Development] lvdoan:
I followed the instructions and successfully installed dual boot. Everything works fine until now.

However, I noticed that though the recovery "GT-P5100_PhilZ-Touch-Recovery_6.26.1-blackhawk.zip" included the NEXT tool, it accessed the extSdCard slower than the recovery "philz_touch_5.15.0-p5110-blackhawk.zip".

Booting into the 1st or 2nd Recoveries and 1st or 2nd ROMs still takes quite sometimes. I don't know the booting speed can be improved.

My device: GT-P5100

1st ROM SlimKat 4.6; "proprietary-vendor-samsung-update.zip"

2nd ROM: Samsung Stock ROM 4.1.2; "proprietary-vendor-samsung-4.1.x.zip"

Recovery: "philz_touch_5.15.0-p5110-blackhawk.zip"

Kernel: "blackhawk-next-kernel-2.2-p51xx.zip"
[Galaxy Tab 2 10.1" Android Development] tetakpatak:
[MENTION=5098617]lvdoan[/MENTION] AMAIK PhilZ 5.xx.xx doesn't work with KK

CWM based recoveries 6xxx need to mount extSD first. Maybe some update will improve the speed. But it is no bug.

I doubt speed of rebooting between the ROMs can be improved. Reboot within one minute isn't bad at all, IMO

tetakpatalked from Nexus 7 flo
[Galaxy Tab 2 10.1" Android Development] lvdoan:
I got ít. Thanks.
[Galaxy Tab 2 10.1" Android Development] Android-Andi:
[MENTION=4021423]ketut.kumajaya[/MENTION] i am really, really sorry... but we forgot something when you came back to tab 2

[YOUTUBE]Ix7vrluEm4E[/YOUTUBE]

:D i know you love that clip :D
[Galaxy Tab 2 10.1" Android Development] ketut.kumajaya:
What a dead thread :laugh: :laugh: :laugh:
[Galaxy Tab 2 10.1" Android Development] Android-Andi:
What a great kernel and what a great human behind the kernel ?! ;) :)

I love NEXT kernel, running great an smooth.

Also i can test most things without breaking my running system.

Info for flashahollics

Add a system.img as

2nd Rom for your daylie driver

ROM.

1st Rom is my testing system

If i am doing on primary-recovery

Wipe Data Factory Reset

Wipe Cache

Wipe Dalvic Cache

format /system

- won't break my 2nd rom :)

(only "format data and data/media" or wipeing the whole Internal Storage in TWRP will delete the 2nd Rom)

I can change my first Rom without problems for testing, also if kernelchanges needs to be tested (then i'll only loose dual-boot for that moment), butr after flashing NEXT Kernel on 1st Rom my Dual-Boot is back :)

But don't forget: Backups never hurt :)
[Galaxy Tab 2 10.1" Android Development] shakatu:
I'm one of the people with the battery drain bug and unfortunately this kernel still has drain on my tab. It showed in battery stats that the tablet was awake for like 8 hours until the battery ran out, but none of the individual apps (including Android system) showed this time... Which makes me sad because I usually stick with your kernels... :(