You dont need IDEFIX software to use a 4 Way addaptor suchas the idefix express with OS4.1 All you need in your Kicklayout is :-
scsi.device.kmod
scsi.device_ppc.kmod (Required for Memory Paging)
ATAPIismajik (Required for 4 way activation)
I notice you are using blizkick (ages since i used 3.x) means your maprom jumper is closed, OS4.1 requires maprom to be open. (NO MAPROM)
If you are using a medaitor check the state of your wait jumper it needs to be closed for OS4.1
Simplest way to set it up is :-
Add 68K smartfilesystem 1.279 Qualifier 53465300 to the RDB
For Dual Boot Without scripts
DH0 - First 1 GB of the disk
SFS/00
512 Blocks
Buffers 600
Bootable BootPri 0
Install OS4.1 from the CD. CDROM-Drive needs to be primary slave.
Create a textfile in sys:kickstart called bootdevice
the contents being DH0
remove the semicolon from the line in your sys:kickstart/Kicklayout-A1200 file
;MODULE Kickstart/BootDevice
HD0 - Second 1 GB of the disk
Same as above
BootPri 1
Put your 3.9 Install here
By default it will boot into 3.9. To boot 4.1 enter the ESS and boot from dh0: the kernel will load, reset and the bootdevice line will tell it to boot workbench from DH0 overriding the higer bootpri of hd0:
Once you have that working then reintroduce your scripts.