D50d looking for SN.ini

Hello.

I have ton configure a Wyse D50d. On my FTP server I use a wlx.ini into the directiry wyse/WLX/.
Why my Wyse D50d is logged on the FTP server, it seem to try to download 88PM7PO522K.ini, this is the serial number of the Wyse (not MAC address, it is the S/N).

Any idea about this issue ?

Thank you.