Chao cac bac. Hien em dang dung may bb9900, may cua em co 1 so van de sau mong duoc cac bac chi giao. Em co 2 van de chua hieu : 1. Khi em thao pin de khoang 1 phut roi lap lai thi time bi sai va date luc nhanh hon, luc cham hon may ngay. ( Co kha nang chet pin cmos?) 2. Em dung sim viettel co dang ky 3 G. Nhung tren bb9900 cua em ko update duoc network time. Nhung khi lap sim sang may bb9300 thi lai update duoc network time. ( em cung thu chay nhieu firmware khac nhau roi, may cua Tmobile) Mong cac ban tren dien dan giup! Thanks.