this receive seems to work well.

It has checksum errors at 123 byte payloads, but this was tested with
the old rftest-tx --- so the transmit side could be the problem.

lib/include/packet.h

@@ -12,7 +12,7 @@ struct packet {
         uint8_t length;
 	volatile struct packet * left;
 	volatile struct packet * right;
-	uint8_t data[MAX_PACKET_SIZE];
+	uint8_t data[MAX_PACKET_SIZE+1]; /* + 1 since maca returns the length as the first byte */
 };
 typedef struct packet packet_t;