Low Signal Strength after Firmware Upgrade When I first bought my Samsung Galaxy S (GT-I9000) phone a month ago, it had it's factory installed 2.1 Eclair running. Despite many 'Android Market' apps not being compatable with it, my signal strength was half to full 3G signal wherever I went.

I then upgraded to 2.3 Gingerbread. My signal strength was lucky to get higher than half strength and often had an E or H next to the signal indicator instead of a 3G ledgend.

I have since upgraded again to CyanogenMod9 (4.0 ICS) with no change to signal strength. In the locations I got full 3G signal only a month ago, I still struggle to get over half signal strength with an H ledgend. The bars are usually grey but occationally turn blue. 

I am wondering if the factory Eclair install had a preset setting making it suitable to work in Australia with the specific frequency bands we have here, and upgrading has over written these settings. If this is the case, my phone may be looking for frequencies used in Europe or America that arn't used here or are the 2G frequencies. 

My googling has found many forum threads where people have lossed signal quality after upgrading, many blaming the carrier or ICS. Several people have subsequently downgraded to default Gingerbread to fix the problem, for me this would mean going back to Eclair. I don't really want to do that.

Is there anything I can do, changing settings or installing an app, that can bring me back to full strength?

UPDATE 26Aug12

I think I have deciphered the signal strength bars. E denotes EDGE (2G) signal, H is for HSPA and 3G for UMTS fast 3G connection. The signal bars are grey normally, and turn blue when you have an active data link (and little up/down arrows show data transfer). 

I wonder if my phone is having trouble with UMTS and therefore not connecting at 3G speeds after the upgrade.
Flashing your Phone probably also changed your Modem/Baseband. Flashing another might give you better Signal.

Here you can download Modems for your phone:
http://forum.xda-developers.com/showthread.php?t=1158783