[LG Optimus 2x] tonyp:
Installation (follow carefully!):

Read post 1 and post 2 completely before you're doing anything with your phone!

If it doesn't exist, yet: Create the folder "external_sd" on your internal sdcard.

Reboot once.

Reboot into your recovery.

If you are coming from another ROM than my Stock ICS:

wipe data/factory reset(!)

Install zip from sdcard (flash the ROM)

Reboot (can take a couple minutes)

After fully booting up and going through the setup wizard: Restart your phone once again

Don't touch the RIL! And don't mind the "Unknown baseband" if everything works. This just means you got one of the older basebands which aren't displayed properly anymore. Nothing to worry about.

If automatic time if off you can either flash the v28g baseband (see my stickyied thread) or disable automatic time and use ClockSync.

Download:

standard version (fits into GB's /system partition):

http://goo.im/devs/tonyp/P990-stuff/ICS

extended version ("full" version requires /system of 512+ mb):

http://d-h.st/CVb

Changelog:

[u]version 3.01[/u]
[LIST]
[*]build.prop lines added to identify it as P990 device in the ROM Manager
[/LIST]

[u]version 3.0[/u]
[LIST]
[*]updated to v28g
[*]CWM Encryption error fixed (you can use any recovery now)
[*]kernel updated. fixes the bluescreen issue and some bugs & memory leaks
[/LIST]

[u]version 2.0[/u]
[LIST]
[*]complete new version based on the v28e leak
[*]no more korean SU660 files, pretty much all bugs are fixed
[*]thanks to harsh who build this version!
[/LIST]

[u]version 0.98[/u]
[LIST]
[*]bsod on screen off fixed (thx arcee!)
[*]huge update to the updater-script
[*]now pre-rooted
[*]Playstore updated
[*]Stock Messaging app replaces LG's one
[*]added Stock LG Browser
[*]added LGAlarm
[*]removed Google TTS
[/LIST]

[u]version 0.81[/u]
[LIST]
[*]typo fix in the updater-script
[/LIST]
[U]version 0.8[/U]
[LIST]
[*]initial release
[*]A mix between the final SU660 v30c ROM and the P990 ICS leak
[*]custom kernel to let it boot with the old bootloader
[/LIST]

Old installation instructions for versions prior to 3.0 (which was way more complex):

Installation (follow carefully!):

Read post 1 and post 2 completely before you're doing anything with your phone!

Create the folder "external_sd" on your internal sdcard.

You need to use ClockWorkMod 5.0.2.x

TWRP & CWM 6.x will result in encryption errors (something to investigate later)

use e.g. RomManager, scroll to the bottom, choose "older recoveries" and install 5.0.2.0

Backup your current ROM

wipe data/factory reset

mounts and storage - format /system

Install zip from sdcard (flash the ROM)

remove the usb cable from the mobile phone!

(if you boot with the phone connected to your PC the PC will either freeze or show you a bluescreen!)

Reboot (can take a couple minutes)

After the setup wizard go to Settings - Connectivity and change the USB connection type to MTP

(now you can attach the phone back to your PC).

Restart your phone

Don't touch the RIL! And don't mind the "Unknown baseband" if everything works. This just means you got an older baseband which aren't displayed properly.

If automatic time if off you can either flash the v28e baseband or disable automatic time and use ClockSync.