A few words about the Optional But Totally Awesome Steam Kernel
Ok, so hopefully you read a bit about it in SzutpY's post. I compiled Steam recovery in English and made a kernel utilizing it. The kernel is similar in many ways to the Universal Lagfix Kernel SztupY also created. It has many of the same lagfix schemes, kernel tweaks, etc, again, all with a touchscreen interface. Other than Steam recovery, this kernel is identical to my 12-23 oc/uv kernel, so it's overclocked, and undervolt configurable, and it should be just as stable as that one.
Do not attempt to take the zImage with Steam recovery and place it in a flashable zip. You'll be a sad panda if you do. I'd advise waiting a few minutes after your system has booted to flash with Neldar's app. If you're using Odin, or Heimdall, reboot to download mode and flash like normal. Those are the options, either Neldar's app (AND NOT Tuxility!!) There are issues with flashing this via redbend_ua - the regular kernel can be flashed via redbend_ua, Steam cannot be.)
Steam recovery is based on ClockworkMod, but you have a touchscreen interface at recovery. Steam has many options to lagfix your system. So, you can have an all ext4 system (including /system), an all jfs system (again, including /system) or something in between. Read through sztupy's posts about Steam, or spend some time playing with it. I have to admit I was a little skeptical of it at first, but after using it for the last week or so, I absolutely love it.
If you're doing a filesystem conversion from Steam recovery, the zeroth thing you should do is check to make sure you have enough room on your SD card to copy /system, /data, /dbdata, and /cache. Then, make a backup. Occasionally after a filesystem conversion, the system will bootloop.
Performing a three button forced reset and rebooting solves this. (In my experience at least. Like I said, make sure to backup first.)
If you do choose a No-RFS lagfix in Steam - Make sure you disable it before flashing another kernel/ROM. No-RFS uses a fake /efs to get a completely-rfs free ROM (only works if /system is set to be mounted as rw).
If it seems as though you've lost su (root)
So, I don't know why Steam does this, but the reason people were losing su was because it was automatically mounting /system nosuid. So, to fix this, there's probably more than one way to do this, but an easy way is to go into Steam, under boot options, select 'Always run adb as root' or something like that. Then reboot, open a terminal and type
Code:
mount -o remount,suid /dev/block/stl9 /system
. That will remount su access to /system (pretty important ), and then you will have root again, and Steam is finally usable again. Flash another kernel or whatever) I was really hoping I could blame this on something MikeyMike did, hmm...I may still find a way. ( Alternatively, it seems if you do a filesystem conversion on /system, /system will be remounted suid so you won't have to go through this, and I think /system conversions don't end up in boot loops like /data and /dbdata.
Credits
Xcaliburinhand - without whom we'd all be on JJ4 and JI6. *shudder*
SztupY - Steam recovery is the shiz.
raspdeep, neldar, xan
I'll probably edit this a few more times as there will be things that I want to add but have slipped my mind for the moment.
Ok - I uploaded a copy of the Steam kernel here. It deserves its own thread and it will get one, just don't feel like doing it right now. Read through this post, realize there are some errors with filesystem conversion. Make sure you do backups, if you get into a boot loops, do a hard reset and reboot normally, you should be good. This is meant to be flashed via Neldar's SGS Kernel Flasher app, or something like Heimdall or Odin.