I wasted many hours troubleshooting this issue and I'm certain there's a compatibility issue between the LSI firmware and IBM drives manufactured by Seagate. I suspect Seagate developed a custom drive firmware for their IBM-branded drives (seems like the sort of thing IBM would do) and it doesn't play nicely with non-IBM controller firmware. I have a wide mix of IBM drives and every drive made by Seagate gives the "illegal request" error and can't be written, while every drive made by Hitachi and other OEMs works prefectly. I tried numerous versions of the LSI firmware and upgraded all the IBM drive firmware. The only fix was to flash the M1015 back to IBM firmware and use it in JBOD mode. Alternatively you could get different drives but finding non-Seagate IBM drives is difficult because they all have the same SKUs; for example, I have two 300GB drives with the same IBM SKU but one has a Hitachi label and the other is a Seagate (Dec 2011 appears to be when they switched suppliers.)
For anyone looking to revert back to IBM firmware:
- Download the latest M1015 firmware from IBM; put in the model of a server (e.g. x3650 M3), find the ServeRAID M1000 series firmware, download the Windows executable, unzip the .exe (yes, it is a self-extracting zip file), and locate the m1000fw.rom in the "image" folder
- Download the .zip from https://forums.laptopvideo2go.com/topic/29059-sas2008-lsi92409211-firmware-files/
- Put all of the above on a FreeDOS bootable USB stick and boot the stick
- Run these two commands to restore the firmware:
megarec -writesbr 0 sbrm1015.bin
megarec -cleanflash 0 m1000fw.rom
And for the record, IBM doesn't restrict firmware downloads to support contracts; you just have to register for an account on their support site.