Sigmatel s90 flight mode
with out sim type*#3646633#
then you wil get eng menu
choose option 5 misc
then choose option 6 assert testing
now menu will open
then select dual mode
TESTED WITH ME
with out sim type*#3646633#
then you wil get eng menu
choose option 5 misc
then choose option 6 assert testing
now menu will open
then select dual mode
TESTED WITH ME