马来西亚带回来的iPhone6可以用联通3G卡吗？4G呢？

需要查看手机是有锁版还是无锁版，此情况建议到手机经销处咨询，不是联通手机卡原因导致。

iPhone6（A1586）版本是支持联通4G和3G的。建议你先查一下你带回来的苹果6是不是这个版本，另外，使用联通4G的话，需要你的联通卡使用4G套餐并开通了4G网络，Mini 3哪个版本支持联通3G或4G，你可以问一下苹果客服4006272273。

联通3G UMTS 2100 MHz
联通4G LTE(Bands 1,3)
马来西亚iphone官网
http://www.apple.com/my/iphone-6/specs/
Model A1549 (GSM)*

Model A1522 (GSM)*
UMTS/HSPA+/DC-HSDPA (850, 900, 1700/2100, 1900, 2100 MHz)
GSM/EDGE (850, 900, 1800, 1900 MHz)
4G LTE (Bands 1, 2, 3, 4, 5, 7, 8, 13, 17, 18, 19, 20, 25, 26, 28, 29)
Model A1549 (CDMA)*
Model A1522 (CDMA)*
CDMA EV-DO Rev. A and Rev. B (800, 1700/2100, 1900, 2100 MHz)
UMTS/HSPA+/DC-HSDPA (850, 900, 1700/2100, 1900, 2100 MHz)
GSM/EDGE (850, 900, 1800, 1900 MHz)
4G LTE (Bands 1, 2, 3, 4, 5, 7, 8, 13, 17, 18, 19, 20, 25, 26, 28, 29)
Model A1586 (GSM)*
Model A1524 (GSM)*
UMTS/HSPA+/DC-HSDPA (850, 900, 1700/2100, 1900, 2100 MHz)
TD-SCDMA 1900 (F), 2000 (A)
GSM/EDGE (850, 900, 1800, 1900 MHz)
FDD-4G LTE (Bands 1, 2, 3, 4, 5, 7, 8, 13, 17, 18, 19, 20, 25, 26, 28, 29)
TD-4G LTE (Bands 38, 39, 40, 41)
Model A1586 (CDMA)*
Model A1524 (CDMA)*
CDMA EV-DO Rev. A and Rev. B (800, 1700/2100, 1900, 2100 MHz)
UMTS/HSPA+/DC-HSDPA (850, 900, 1700/2100, 1900, 2100 MHz)
TD-SCDMA 1900 (F), 2000 (A)
GSM/EDGE (850, 900, 1800, 1900 MHz)
FDD-4G LTE (Bands 1, 2, 3, 4, 5, 7, 8, 13, 17, 18, 19, 20, 25, 26, 28, 29)
TD-4G LTE (Bands 38, 39, 40, 41)