stuck at boot screen
I doubt that adding some ringtones to your /system/media folder from your PC would result in a non-boot condition. Sounds like you may have messed up some system files when you were doing what you were doing. Are you sure you did not inadvertently move/delete/alter any other files?
Do you have an unlocked bootloader?
I have a similar problem and I know I am not bricked but can't currently get out of my jam. This is the process I used so far:
I unlocked bootloaders and rooted with an automatic script program
I installed superuser and CWM from the market
I placed the cm-7.2.0-olympus and gapps .zip files in my root of internal sd
I wiped with moto-fastboot followed by wipe data/factory reset, wipe cache, and Dalvik
Then I installed the CM7.2 and Gapps zip files from the sd - and now I'm stuck at the M boot screen with Unlocked at the top.
I can boot into recovery and at the top of the recovery screen it reads Atrix 4G Recovery v4.0.0.2 goapk.com so I am thinking that the script I used initially installed a different recovery program and I am not actually using CWM. Also when I get into fastboot mode it says my battery is too low to flash and I don't have an indication that the battery is accepting a charge when it is plugged in...
I can get into recovery but even if I wipe and reinstall the zip I can't get past the boot loop - any suggestions?