Could be. At least I'm also using a SCSI adapter with the AIC7XXX driver: scsi0 : Adaptec AIC7XXX EISA/VLB/PCI SCSI HBA DRIVER, Rev 7.0 <Adaptec 29160B Ultra160 SCSI adapter> aic7892: Ultra160 Wide Channel A, SCSI Id=7, 32/253 SCBs -- Kernel 2.6.15-21 does not boot https://launchpad.net/bugs/41141