2.2 froyo - How do I turn off the cellular radio without disabling bluetooth?

I have an old Motorola Droid that is no longer subscribed on any Verizon service. I still use it for things like web browsing, ebooks, and along with some wireless stereo headphones, music. I've already turned off 3G data usage (EVDO) by disabling the Enable data option under Mobile network settings. However, when I turn off the cell radio (CDMA), bluetooth is also disabled. I first observed this problem on the stock Android 2.2 firmware. Now my phone is rooted, running on an Android 2.2 based firmware (CyanogenMod 6).

Why disable the cellular radio?

Simply put, I want to turn it off because I don't use it. Moreover, it uses battery life and cpu time (even if relatively small amounts):

I've tried two different methods of disabling the cellular radio, but both ended up doing the same thing:

• Turning on Airplane mode, then re-enabling Wi-Fi. This has the expected consequence of also disabling bluetooth.


• Using the Phone Info menu by dialing *#*#INFO#*#* (4636) and pressing Turn off radio. This actually just turns on Airplane mode:
  

As you can see, even though Wi-Fi does stay on, Airplane mode disables bluetooth. The headphones won't sync until I turn off Airplane mode, which of course turns the cell radio back on.

In both cases Airplane mode is enabled, so bluetooth gets disabled. But now that the device is rooted, I should be able to disable the cellular radio without using Airplane mode at all. How can I do that?

Answer

Check out this guy's post on XDA: http://forum.xda-developers.com/showpost.php?p=11370203&postcount=2

This might be considered a risky solution, but if you aren't using the 3G connection at all and you're careful to simply rename the .apk's he references you might just disable the cell radio without needing to use Airplane Mode.

In case the link doesn't work, he suggests using Root Explorer to rename phone.apk to phone.apk.bak and telephony.apk to telephony.apk.bak thus disabling these two packages. You have to reboot your phone to finalize the changes. If it doesn't work, you should remove the .bak from each file name and they should be available again.

At OP's request, a summary of his findings:

Phone.apk is the Dialer app, which is responsible for the cell radio. PhoneTelephony.apk turns out to be just the Dialer storage, which we can kill just to save more memory. AndroidOS immediately restarts Dialer when it is closed, so renaming it will cause problems. But after a battery-yank-reboot, everything is ok. It also gets rid of the annoying Activate your phone dialog that comes up on every boot. btw, the dialpad still comes up after getting rid of Dialer :-)