FIrst, sory for eventualy double posts.. I'm new on forum. I have a SG S4 mini and sometimes i recive mesage : Sim card removed, please restart device " I'm now on Lolipop...If i go back to 4.42 can my problem be resloved ?
Welcome to Android Central! Moved to the S4 mini forum.
The SIM slot might be dirty, or the mechanism to hold the card in place might be loose. Take the card out and use a can of compressed air to blow out the slot, then see if the problem persists.