[Defy Q&A, Help & Troubleshooting] cengiran:
hi there,

i have the same issue but not due to CM9 installation but due to hardware issue. judging by your writing, this has nothing to do with software and so hopefully this helps.

My screen is also black at boot with some part of it are stripes (and some bad white and blue square w/ noise) and looks like a broken LCD monitor.

This is due to hardware malfunction (probably your battery went bad) in my defy the battery have some water damage and somehow it screws up the voltage regulator or the grounding part, but does boot with the correct screen using some techniques on every boot.

Try this solutions:

1. completely discharge your battery, take it off, hold the phone power button for 30 seconds to make sure every power stored in phone is out. Put the battery back on and connect the charger while the phone is still off. DO NOT turn the phone on. Your screen will look all mess up when showing the green battery, wait until 3hours and take a look at your screen again. In my case, the screen showing the the battery charging image is clear again after i did this. - this is to make sure that your screen is actually okay. Try turning your phone now and see...if its still bad then go to step 2.

2. turn phone off, open the battery case. Connect phone to charger again without turning it on. The phone will do its regular boot up until showing you the battery icon again. when the battery icon is there, PULL the BATTERY out of the phone (the charger cable is still connected to the phone). the phone will reboot itself with the correct screen usually, if it doesnt boot itself, quickly pull charger cable and reconect it again (with the battery still detached from your phone).

mind you if you get to the okay screen, this will not boot your phone, this will bring you as far to the battery icon with a question mark (we know for sure is just battery issue now). regardless screen is okay or not, proceed to step 3.

3. turn off phone, battery out of the phone, and press the power button for 30 seconds. release power button and re-insert battery and boot. (usually still bad but this is to ground any left voltage in there). after it boots (with the bad screen, if the screen is okay then proceed to using your phone like usual) before the LED lights blinks (the 2nd.init lights) pull out battery, press the power button for 2 seconds, re- insert, and boot. repeat this as necessary until it boots with an okay screen.

tips:

battery empty is for step 1 only, steps 2 and 3 needs power form the battery.

You can actually go to step 3 if you wishes, but my experience is by using step 2, it will talke less retry until i boot with the okay screen (i need to do this everytime i restart the phone mind you, so its a daily thing) .

the LAST tip: there no rules of thumb on how many retries it needs, if you have been retrying for 20 minutes on step 3 with no avail, revert back to step 1 or 2 and retry step 3. If this is sill fails, then you might need to consider purchasing a new battery, or take it for a repair!

Im still waiting for my new battery, but now it only takes me 5-6 tries before it boots correctly, in the apst it took me 15 minutes of constantly retrying so be patient, but still need to set a line when to give up!

Hope this helps and good luck