If you have the control over TX side, you can pull the TX pin low for say 100ms, then your RX routine jumps to Interrupt routine and wait for the serial data to come in. So you do not lose any bit.

Or, assuming you can control the TX side, you can send two bytes instead of one byte. First byte, %10000001, will interrupt the RX side, and you will receive the second byte. This may cause issues though.