boot in recovery
mount system partition
adb pull /system/customize/ACC/default.xml
search for sku_id
change the value from 10 to 6
and push it back to device
adb push default.xml /system/customize/ACC/
HFA will not bother you any more.
however you will not be able to use any of the ## commands. which is anyways not required for GSM
for DATA on CDMA network only way to get it working to manually define APN.