How to put ICS on rooted SGS2 with Gingerbread 2.3.6

[AmitX123]

Hi, I recently rooted my phone which is running Gingerbread 2.3.6
However, 2.3.6 has the "random reboot" problem when SD card is inserted (the problem was there before root as well).
I want upgrade to ICS to solve this problem. My questions are:

1. Can I upgrade the OS without losing root?
2. What is the best way to do it and which ICS version do I get?
3. Can I do it without losing my data/settings?

Right now there are so many sites that it is overwhelming to study them myself. Several of them are also incorrect, so I don't want to take any chances of bricking my phone.

My phone details
Samsung Galaxy S2 i9100
Build number: GINGERBREAD.XWKL1
Android version 2.3.6

 

[ironass]

Hi, I recently rooted my phone which is running Gingerbread 2.3.6
However, 2.3.6 has the "random reboot" problem when SD card is inserted (the problem was there before root as well).
I want upgrade to ICS to solve this problem. My questions are:

1. Can I upgrade the OS without losing root?
2. What is the best way to do it and which ICS version do I get?
3. Can I do it without losing my data/settings?

Right now there are so many sites that it is overwhelming to study them myself. Several of them are also incorrect, so I don't want to take any chances of bricking my phone.

My phone details
Samsung Galaxy S2 i9100
Build number: GINGERBREAD.XWKL1
Android version 2.3.6

In answer to your questions:-

1. No. You will have to re-root after flashing. See guide here.

2. The ICS will depend on which CSC code you are on if you wish to flash an official, stock, ICS firmware. See under, "My firmware is not eligible for ICS yet but I want it now!", in post #1, here.

Alternatively, you could flash a custom ICS ROM, such as AndyX, from here.

3. "In theory", you should not lose your data and settings when flashing a stock ROM... however, it is always advisable to do a nandroid and Titanium backup to be on the safe side. For details of these, see here.