1. Ok first get the app Tailor from Preware or quickinstall. This app is kinda like partition magic for webos.
Originally Posted by Jonspeed
2. Then read up this wiki about the apps to familiarize yourself with this app found here: Application:Tailor - WebOS Internals
3. Then you will open the app Tailor to start nuking partitions. In the app you have a few boxes; the partions and select activity you focus with first. In the partitions box, delete the android partitions one by one. Tap on each android partition and then in the select activity box change activity to delete partition and hit the red button. Do this for all other android partitions. LEAVE THE USB MEDIA PARTITION ALONE, for now.
4. Now all the sudden you have some unused space that will be reincorporated into your USB media partion. Take note of the partition size for USB Media and Unused Space. You will get this info by tapping on each of these 2 and in the activity box jot down the partition size there in MiB. Now add those 2 together and the sum will be the new size of the USB partition you will do shortly.
***Do you have any USB data that you really want to save? Now is the time to back it up!***
5. Time to resize the USB partition back to stock. Tap on the USB (media) partition and in the activity box below do unmount partition. Next in activity box do check filesystem. After that, in the activity box select resize partition. For the partition size, take the sum you calculated in step 4 and input it in. Afterwards, do check filesystem again before mount partition back.
Thats it! There is a chance the resizing of the USB partition may have nuked some of your data there as this is a calculated risk. Reboot the device and try to install CM7/9 in. Make sure you are using ACMEInstaller2 with CM9.
Like I said earlier, if the install still fails, use tailor to make sure the android partitions are not there and run the 3.0.0 webos doctor from the link I gave you in my previous post.