Sorry to hear about your problem.
my 2 cents to try to help you is my u-boot config in case there is something in mine that would boot OS4 that you might not have...
11.DH0:> nvgetvar
amigaboot_quiet=N
amigabootmenu_animcycles=1
baudrate=115200
bdev=sda3
bootargs=root=/dev/sda2 mem=3500M console=ttyS0,115200 console=tty0
bootargs_live=root=/dev/ramdisk boot=casper mem=3500M ro --
bootargs_live_debug=root=/dev/ramdisk boot=casper mem=3500M ro break debug
bootcmd=setenv bootargs root=/dev/$bdev rw console=$consoledev,$baudrate $othbootargs;tftp $loadaddr $bootfile;tftp $fdtaddr $fdtfile;bootm $loadaddr - $fdtaddr
bootdelay=5
bootdvd=scsi reset ; load scsi 0 2000000 boot_dvd ; bootm 2000000
bootfile=uImage
bootmenu_waitticks=50
consoledev=ttyS0
eth1addr=00:50:C2:20:DA:CC
ethact=FM1@DTSEC4
ethaddr=00:50:C2:20:DA:CB
ethernetboot=echo Running Ethernet Boot
ethprime=FM1@DTSEC4
fdtaddr=c00000
fman_ucode=7fe73478
harddiskboot=echo Running Hard Disk Boot
hwconfig=fsl_ddr:ctlr_intlv=cacheline,bank_intlv=cs0_cs1;usb1:dr_mode=host,phy_type=utmi;usb2:dr_mode=host,phy_type=utmi
kbddev_norwin=1
linuxboot=echo Running Linux
liveusb=usb start ; setenv bootargs_live_debug ; ext2load usb 1:1 2000000 boot_dvd ; bootm 2000000
loadaddr=1000000
loadbmps=mmc read 0x10005000 0x500 0x200; mmc read 0x20000000 0x10000 0x20000
massboot=echo Running Mass Storage Boot
mos=bootmorphos
netdev=eth0
nfsboot=setenv bootargs root=/dev/nfs rw nfsroot=$serverip:$rootpath ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname:$netdev:off console=$consoledev,$baudrate $othbootargs;tftp $loadaddr $bootfile;tftp $fdtaddr $fdtfile;bootm $loadaddr - $fdtaddr
opticalboot=echo Running Optical Boot
preboot=run loadbmps;bmp d 0x20000000;ami
ramboot=setenv bootargs root=/dev/ram rw console=$consoledev,$baudrate $othbootargs;tftp $ramdiskaddr $ramdiskfile;tftp $loadaddr $bootfile;tftp $fdtaddr $fdtfile;bootm $loadaddr $ramdiskaddr $fdtaddr
ramdiskaddr=2000000
ramdiskfile=ramdisk.uboot
rootpath=/opt/nfsroot
scsidevs=1
sii3112ide_conf=01
stdin=usbkbd,serial
stdout=serial,vga
uboot=u-boot.bin
ubootaddr=0xFFF80000
