ios IBM 5170 hard disk with 47 user

I'm trying to install a hard drive IBM H3256-A3 (manual here <http://www.hgst.com/tech/techlib.nsf/techdocs/7BF937434F9F7BBC86256E9000734 60D/$file/oem3fspe.pdf> http://www.hgst.com/tech/techlib.nsf...e/oem3fspe.pdf ) in an IBM AT 286. I state that the motherboard 286 type 1 with a controller AB-862G SUPER MULTI I/O CARD and a pair of drive performs the correct boot of the dos 4.0 (with no hard disk connected and configured), and that the alone hard drive works and has been perfectly formatted in dos way on another P3 machine. I replaced the original U27 and U47 with the bios BIOS_5170_30APR89_AMI_D286-1277-043089-K0 (downloaded the AMI BIOS FOR 5170 at the bottom of this page <http://www.minuszerodegrees.net/bios/bios.htm> http://www.minuszerodegrees.net/bios/bios.htm) to have the option 47 user disk. Following the instructions given in the manual of the hard disk IBM H3256-A3 fields to be filled in bios are: cyl = 872, heads = 16, Wpcom = 65535, Lzone = 0, sect / trk = 36, obtaining a total capacity of 245.205 MB (=872x16x36x512/1048576). After turning on the machine, however, it stops and it does not proceed either boot from a floppy or even the keyboard responds any more. Instead without hard drive connected and / or configured the machine works perfectly. Thanks for any useful suggestion. Enrico