I have a Team 4GB, and ADATA 2GB that work in my 1400, but that is IDE to begin with, not some odd SCSI contraption. :p
Also, if the 4GB card is FAT formatted on a PC then 7.6.1 will not like it. but if you make it exFAT or FAT32 or something 8.6 has no issues.(one of the two or possibly...