Generally, this disclosure provides systems, devices, methods and computer readable media for patch downloading, from a host to a target, with improved acknowledge (ACK) mechanisms including combinations of out-of-sequence, single and aggregate acknowledge mechanisms. The method may include determining a packet size based on buffer capacity of the host; calculating the total number of packets (P) for transmission based on a size of the patch divided by the packet size; and calculating a packet storage capacity (N) of the target, based on buffer capacity of the target divided by the packet size. The method may also include transmitting the P packets to the target, including a sequence number and a portion of the patch, the transmission segmented into one or more cycles of up to N packets. The method may further include receiving ACKs from the target (asynchronously relative to the packet transmissions), the ACKS associated with the sequence numbers.