If I happen to lose the first byte of the Packet1,
You need to add 2 more bytes: a start and stop char so one packet becomes something like
< packettype data CRC >
// yes it looks a bit like XML
has char 2 and 3 defines as Start of Text and End of TExt can also be used.
after receiving the > character you know you must have 5 bytes to work with, if not one is lost
if don't you receive a > char but a < char you know there is something faulty too
And yes there is a chance that the CRC code contains a > stop char.
This is the way to get in sync with the sender. just read until you got "><" a stop followed by a start.
Hopes this helpes,