[HELP] AVM C2 Freezes


I’m building an asterisk box with a debian testing.

Initially, it worked correctly with an AVM Fritz! ISDN card. Then I added an AVM C2 card (ISDN active). I use kernel module c4. When I try to stop capi (/etc/init.d/capiutils restart), linux freezes, without any error message. If I don’t load the firmware, everything is fine.
I tried booting with noapic and acpi=no options, no change.
I’ve tested kernel 2.6.8 and 2.6.12 with firmwares 3.09-11 and 3.11-06. I also removed Fritz!Card.
Then I changed my motherboard, and now I can do “capiutils restart” one or 2 times before system freezes.
I’ve enabled capi and c4 module debugging, there is no message.

AVM support told me that it should work with a SuSe…

Could someone help me ?