From your other reply in the S2 thread:
ok, so I screwed up my phone again this morning... (and this time I definitely followed the instructions to what I was doing 100%) see thread from yesterday here
Im following this video here, to try and get CWM installed.
http://www.youtube.com/watch?v=3vW7W4Mj-Js Infortunately when I try that, Odin says failed and then Im back to a phone that needs to be fixed again.
I have verified that the phone has root access, so Im a little confused as to why this process is crashing.
I figured that maybe what I was trying to do was an issue because I didnt have root. So I followed this I guess that sorted the root, but when I go into Recovery mode it still has the default and not the CWM. Thats not right?
Forget that video, just follow this guide:
http://forum.xda-developers.com/showthread.php?t=1505172
In summary:
Make sure you have Odin installed and it recognises the phone.
Go to Settings-> About Phone and look for you kernel version. Mine ATM is 3.0.15-19100DX
LP7-CL233393.
The bold part is important - LP7 in my case.
Go to this page and look for a kernel that has the same version as yours:
http://forum.xda-developers.com/showthread.php?t=1103399
In my case there are two:
CF-Root-SGS2_DX_XTC_LP7-v5.4-CWM5.zip
CF-Root-SGS2_XW_XEN_LP7-v5.4-CWM5.zip
I could choose either one, does not matter. Once you have found your kernel, extract the file until there is only a zImage file (it is packaged twice).
Put the phone in "download mode". Switch off phone. Hold volume down and home button, press power on and keep all buttons depressed. You will get a warning that you are entering "Download mode", just follow the steps to continue using this mode.
Now simply connect your phone to USB and use Odin to flash the zImage. Once done the phone will reboot and you will know that it worked since you will get a yellow warning triangle while the phone powers on.
That is it, you are now rooted and CWM recovery is now installed.
Update the SuperSU software and reboot.
To get into CWM recovery you can either use volume up+home+power or enter the CWM app and choose to reboot into CWM recovery.
Now you are ready to install a ROM.