YModem transfer error via serial (COM port)

First sending package error, when I tried to send file via serial (COM port), first packet contains only 3 bytes ('r', 'b', '\n'), but must contain transfer packet, begin with 0x01 for 128byte transfer. First package must be:

SOH 00 FF filename filezise NUL CRCH CRCL

where SOH = 0x01

Tested on windows and linux

No source file or test is named in the issue. Reproduce the first-packet failure on a serial connection under Windows or Linux, then trace the YModem sending entry point. Done means the first packet is a 128-byte transfer packet beginning with SOH (0x01) and containing the filename, filesize, and checksum fields described in the report.

Written by the indexing model from the issue text.