A method for minimizing the loss of data and ensuring that large delays do not occur during reconfigurations of an uplink transmission time interval (TTI) length of a WCDMA High Speed Packet Uplink Access (HSUPA) air interface, wherein the reconfiguration of an uplink TTI length is delayed until all pending retransmissions are successfully transmitted or until the maximum number of transmissions is reached. The transmission of new packets during this time period is prevented. However, pending retransmissions are allowed to occur. After the UE has received an ACK/NACK for each HARQ process, or until the specific maximum number of re-transmissions is reached, the UE starts transmitting with a new uplink TTI length.