It should
not say "Waiting for flash" at the end unless
- You typed "start autoupdate" again
- You're using an old version
The log does not indicate any problem, just that it stopped when writing vendor.
The division between stdout and stderr by the update engine is stupid.
Try again using the new download.
Errors accumulate easily on flash drives.
Reformat, write the two files, chkdsk /f