Nick: icon
E-mail: none
Board: ch347
Contents: 
diff --git a/ch347_spi.c b/ch347_spi.c
index 71700f01590f..715f7e308264 100644
--- a/ch347_spi.c
+++ b/ch347_spi.c
@@ -167,12 +167,12 @@ static int ch347_read(struct ch347_spi_data *ch347_data, unsigned int readcnt, u
                        msg_perr("CH347 returned less data than data length header indicates\n");
                        return -1;
                }
-               bytes_read += ch347_data_length;
-               if (bytes_read > readcnt) {
+               if (bytes_read + ch347_data_length > readcnt) {
                        msg_perr("CH347 returned more bytes than requested");
                        return -1;
                }
                memcpy(readarr + bytes_read, buffer + 3, ch347_data_length);
+               bytes_read += ch347_data_length;
        }
        return 0;
 }