Seems that Herald bootloader password is static:
If you enter this password in mtty terminal, you won't be able to boot device into Windows, only in bootloader. Be careful.
A possible workaround is to send a set 14 0 command so the device exit the flash mode.
Another option is to issue those commands (original thread)
password BsaD5SeoA ruurun 0 ResetDevice
(None of those options were tested)
Other Commands for Canon Yang's SPL:
cpldver SetDsbDBGMSGT ClearDBGMSG ReadExtROM emapiWlanMac emapiPwrDwn emapiRead emapiTest emapi getdevinfo ruustart ruurun progress wdata password set SetDebugMethod checksum ResetDevice BTRouting