S2 GT-i9100 - TWRP flash unsucessfull (Heimdall)- can't identify reason - Galaxy S II Q&A, Help & Troubleshooting

Hello!
First of all, I'm not a native speaker so let me know if there is something that is not clearly stated / confusing.
I got a little problem with my phone and was unable to find a solution to my problem in this forum or anywhere else so I just registered moments ago
My phone: Samsung Galaxy S2 GT-i9100, running freshly flashed stock ROM (android 4.1.2 , stock recovery)
*HISTORY*
I tried to flash a custom recovery and after soft-bricking it I flashed a "stock ROM" from Samsung which I found on the internet and everything works perfectly again.
However, this shouldn't be of any relevancy to the following problem(s).
*WHAT I WANT*
I want to install the latest snapshot build of Cyanogenmod 12.1 (I would choose CM13 but there are only nightly builds and I don't want that).
As I'm new to all of this I followed manuals which told me to install the custom recovery "TWRP".
To do so I followed this manual: https: //twrp.me/devices/samsunggalaxys2i9100. html
and used "twrp-3.0.2-1-i9100.img"
*THE PROBLEMS*
After Heimdall tells me that everything was successfully flashed (noreboot is set) I turned the phone off and restarted it straight to recovery mode.
Instead of booting the TWRP custom recovery which I just flashed the android stock recovery was booted.
QUESTION 1: Does anyone have an idea why that happens?
As far as I know there is just a 'vestigial' recovery partition on the i9100.
Apparently 'isorec' offers a way to make it available for my custom recovery so that TWRP does not get overwritten by the recovery
which is part of the CyanogenMod (which I'm going to install later on). Is that correct?
QUESTION 2: Is there anything I need to do to make isorec work which is not covered by the manual I use?
Apparently the system partition is too small for CyanogenMod13 + GoogleApps (but I want to use both later on).
QUESTION3: How can I repartition, how much space will I need and how do I do it? Do I have to do it before I flash recovery or before I flash the CM12.1 ROM?
So far I found several really unspecific tutorials and now I'm afraid to brick the phone.
Looking forward to any advice, thanks a lot!
blackdaw

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Hi @blackdaw
I'll explain what went wrong and how to do what you want...
1. The TWRP 3.0.2-1.img is a isorec recovery. It won't boot unless you have an isorec-enabled kernel. If the kernel you have is not, then the recovery that is bundled with the kernel is booted instead(ie. the old style monolithic kernel/recovery in the kernel partition). So you need a newer kernel(which means a newer rom that runs with a isorec enabled kernel). Until you have that don't worry, we'll get to that.
2. Re-partitioning. You will eventually need to re-pit, as the newer roms(android 6+) often need a bigger system size even if you don't use gapps. 1GB should be ample. Here is a good guide for updating to MM roms, but also has links for re-partitioning. Take your time and study the different ways to re-pit, but personally I would just re-pit before flashing any roms, then it's done. I use odin(windows) and re-pit at the same time as installing a recovery using this method. As I said there are other ways....
3. What I would do:
Odin re-pit method
*I use gustavos kernel to flash with odin at the same time as the .pit file. Some .tar kernels don't work(Idon't know why)
Once you are in the TWRP/CWM recovery, do your backups/wipes and flash the rom and gapps(if you want) and TWRP 3.0.2-1.img, then reboot.
(No yellow triangle method)
download a kitkat compatible kernel such as the one I've attached
find the correct philz kernel for your stock rom from here. It needs to be in .zip format. Flash the kernel in the stock(3e) recovery, then reboot to recovery. This is all you need to flash older custom roms(you will be rooted and could stay on stock if you wanted but the recovery is obsolete for kitkat and above)
from the new philz/CWM recovery, flash the TWRP kernel I attached then reboot straight to recovery once again. (This kernel won't boot the rom; you will end up with a bootloop if you try. You only need the newer recovery)
now from this TWRP 2.8.7.0, flash the TWRP 3.0.2-1.img just to make sure you have that recovery installed to the recovery partition, and CM12.1(*note below) and gapps(if you want).
use Lanchons re-pitting tool to re-partition
Install diskinfo app from the store to check your partition sizes and if you want an easy way to see free space etc.
Note: I would strongly recommend you use the last nightly or newer unofficial build of CM12.1 if you are set on that rom. There are several major fixes(including the implementation of isorec) that are not included in the last official snapshot build. I've uploaded the last nightly here
I hope I've covered everything. Happy flashing

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Hello noppy22,
thank you so much for your reply! I literally spent days reading all sorts of stuff so I would know and understand all alternatives and not brick my phone. However, I didn’t succeed so far, I’m stuck with the first step where I am supposed flash the philz kernel as preparation for flashing the TWRP stock kernel (which you attached).
So far I had about 15 different attempts with different methods but I try to remember what I did and what went wrong:
First I tried to repartition and flash the philz kernel
(versions “philz_touch_6.07.9-i9100.tar.md5” and “philz_touch_6.05.6-i9100.tar.md5”)
at the same time, following the manual you linked under “this method”.
Here is the log of what happens:
<ID:0/004> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> philz_touch_6.07.9-i9100.tar.md5 is valid.
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/004> Odin v.3 engine (ID:4)..
<ID:0/004> File analysis..
<ID:0/004> SetupConnection..
<ID:0/004> Initialzation..
<ID:0/004> Set PIT file..
<ID:0/004> DO NOT TURN OFF TARGET!!
<ID:0/004> Get PIT for mapping..
<ID:0/004> Firmware update start..
<ID:0/004> recovery.img
<ID:0/004> NAND Write Start!!
It was stuck at “NAND Write Start!!”. After a long, long time I just pulled the cable.
Afterwards I booted into recovery and tried flashing zip files of the same philz kernels.
Here I encountered an error looking something like this: “ This package is for "9100, …, …" devices; this is a ‘’ “
Instead it should say “ this is a ‘9100’ “ but the space between the ‘ ‘ is just empty, it doesn’t seem to recognize my device.
Others have this problem too: http://forum.xda-developers.com/showthread.php?t=2602107
Next thing I tried was the manual in cyanogen wiki:
(https:// wiki.cyanogenmod.org /w/Install_CM_for_i9100 )
Before the softbrick (as mentioned in first post under ‘history’) this enabled me to use CWM recovery.
Now that I tried it again it does not work any more, saying something like “no kernel partition detected”.
I thought this problem was caused by the new partitioning so I used the repart option in odin together with stock PIT-file. No success.
Now I ran out of options, I tried everything that came to my mind.
Any idea how to fix this? Try fifferent Kernel? I was not brave enough to pick one on my own.
Btw, after all this messing around I’m stuck in bootloop but can still reach Download Mode and Stock recovery.
If you need more detailed information/logs I'll try to reproduce the errors.
Thank you so much, I'm quite desperate!
All the best, blackdaw

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Hi @blackdaw
I realise reading your post I was a little unclear on a couple of points. Sorry about that. I'll edit my post above to make it clearer for anyone needing the same help.
All you need to do is flash this kernel I've attached, in odin. Just untick reboot device and when you get a pass, turn off the device and boot into recovery. You will get a bootloop if you try to boot your rom. Before you do this, make sure you have your rom and gapps(if you want them) ready to flash from this new recovery.
Alternatively find the stock rom from sammobile.com and flash the .tar.md5 file from odin and start again. This is usually my goto step if I've messed anything up.
The two points I didn't explain very well were to use philz kernel in .zip format to flash from stock recovery before re-pitting, and I didn't explain when to re-partition. Again sorry about that.
EDIT: I've edited my first post. Hopefully it explains thing a bit better. Let me know how you go

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Hi @noppy22,
it works, thank you so much!
So here is what I did in the end:
1. First I followed gsstudios guide to Increase system partition size and used all the software he attached.
The Samsung drivers were already installed so I launched Odin 3.07, loaded the "I9100_1GB-System_4GB-Data_512MB-Preload.pit" in the pit file section, checked "repartition", unchecked "reboot", loaded the "AOSP-LP-Kernel+_26-07-2015_TWRP-2.8.7.0.tar" (which you attached in your last post) in the PDA section and hit start. It took a while but in the end the odin log said something like "1succesfull / 0 unsuccessful"
2. After turning the phone off I rebooting to recovery mode which was now TWRP 2.8.7.0. Just to have the latest version I wanted to flash TWRP 3.0.2-1 but I didn't work because the device was "unable to mount emmc".
However, I justed flashed "cm-12.1-20160203-NIGHTLY-i9100" which you linked to in your first post and rebooted to system. TA DA! It worked!
There was still a problem with the storage. The now 4GB large Data partition and the 32GB external SD-Card were visible but not the 9GB internal SD-Card (UMS) wasn't. After rebooting to recovery to fix the problem a little surprise awaited me: TWRP version 3.0.2 was displayed, even though the previous update pretended to have failed. Well, I can't complain. Wiping the Data partition resolved the problem so android could successfully mount it.
End of story.
Now that everything is working, how can I get updates to the latest CM version? What really puzzles me is that they deleted the latest nightlys of CM12.1 and only left CM13 nightlys on the official CM download page.
Where did you get the CM12.1 nightly version you uploaded?
Is it safe to just do and OTA update?
I read in that one thread that OTA update is not safe for CM13 so if I find a reason to flash it I'll do it via recovery.
Thanks again!
All the best,
blackdaw

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Hi @blackdaw,
I'm glad you got it working! The step you missed straight after the re-partition was formatting the new partitions from recovery. Especially sdcard0: without formatting sdcard0, the system will normally report that as corrupted or unable to read.
The 3.0.2 TWRP only booted after you had flashed the isorec enabled kernel(that is, by flashing CM12.1) The older kernel you used re-pitting wasn't isorec enabled, and so it used its own bundled TWRP 2.8.7 recovery. This was over-written by the kernel in CM12.1 when you flashed it......TWRP 3.0.2-1 will now work whenever you have isorec enabled kernel/rom and you don't need to flash it again; it will survive any normal wipes or flashes you make as it resides in the recovery partition.
Don't use OTA when you want to upgrade to CM13. You will need to do a full wipe and install with recovery.
The CM12.1 I still had on my computer from when it was on the CM page. They normally wipe older builds and keep newer ones for space I imagine. They will keep "snapshot" builds a lot longer, but CM12.1 never got a final snapshot, and we've never got a snapshot CM13 build despite being mostly stable depending on when they introduce new features/commits. Check on posts in the official CM13 thread for more info on bugs and which versions are more bug-free.
Good luck

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Changing kernel sorts all issues
Changing kernel sorts all issues, thanks you for your help. :good: