Hi Bjorn, If you carefully read the lspci information you just sent me, your 537 board suffers from the exact same odd problem as the two 537 modem owners (in Ireland and in India). You can read in your data this line: Kernel driver in use: serial The "serial" driver is nothing but the 8250_pci.c kernel code, which conflicted with the 537 driver. This is something I did rule out in my latest 536EP/537EP code. As of today, this "serial" driver gets unregistered by the 537 driver. You do get this above information because your 537 board is a "Communication controller" and has exactly one or zero memory region and one I/O region. The 536EP board has exactly one memory region and zero I/O region, hence the 8250_pci.c code not thinking he has to handle the board. The 8250_pci.c kernel code does lack blacklisting many Winmodems boards. It just blacklists the AC'97 ALI modem which happens to be also handled by 537 driver. Yours truly, - http://vouters.dyndns.org:8080/ Philippe Vouters (Fontainebleau/France) Le mardi 07 juillet 2009 à 18:54 -0300, Bjorn Wielens a écrit : > Kernel driver in use: serial