[Help me] Iphone 3gs 4.3.5 ha Fw xuong 4.1 gap loi 1013 treo Recovery

Minh moi di xuat khau lao dong o nuoc ngoai, vua mua con IP 3gs nhung FW la 4.3.5.
Minh da thu lam moi cach de unlock nhung ko dc. Minh quyet dinh ha FW xuong 4.1 nhu huong dan cua moi nguoi tren mang. Khi lam thi minh gap loi 1013 bi treo cap dia, lam moi cach ma khong the nao thoat duoc. Minh moi tim hieu ve Iphone nen ko co kinh nghiem.Vi vay minh xin hoi y kien moi ng co cach nao xu ly loi ko?
Rat mong duoc su giup do cua moi nguoi. Thanks