The installer uses de4x5 for some DEC FE cards, like:
00:0a.0 Ethernet controller: Digital Equipment Corporation DECchip 21142/43 (rev 30)
de4x5 doesn't work in forced full duplex IIRC and hasn't really been maintained that much.
Using 'tulip' would probably be better.
Assigning to a developer.
Fixed 12/27 (in beta 2)