FC2 => FC5 panic on first boot

[C6_bandini]

Hi,
I just upgraded a Fedora Core 2 to a Fedora Core 5.
My system does not boot anymore :

(Kernel panic)

I tried to boot in single mode, so I modified the grub kernel line as follow

ro root=/dev/hdd1 rhgb single console=ttyS0,115200

And here is the end of the output :

Write protecting the kernel read-only data: 359k

Red Hat nash version 5.0.32 starting
Mounting proc filesystem
Mounting sysfs filesystem
Creating /dev
Creating initial device nodes
Setting up hotplug.
Creating block device nodes.
Loading jbd.ko module
Loading ext3.ko module
Trying to resume from /dev/hdd3
No suspend signature on swap, not resuming.
Creating root devicinput: ImPS/2 Generic Wheel Mouse as /class/input/input1

e.
Mounting root filesystem.
kjournald starting. Commit interval 5 seconds

EXT3-fs: mounted filesystem with ordered data mode.

Setting up other filesystems.
Setting up new root fs
no fstab.sys, mounting internal defaults
Switching to new root and running init.
unmounting old /dev
unmounting old /proc
unmounting old /sys
Kernel panic - not syncing: Attempted to kill init!

[<c011a32e>] panic+0x3e/0x170 [<c011cede>] do_exit+0x71/0x6c8

[<c0145fe5>] do_munmap+0x184/0x19e [<c011d5b9>] sys_exit_group+0x0/0xd

[<c0102bc1>] syscall_call+0x7/0xb


What can I do ?

[C6_bandini]

Here is what I did after this :
I booted my system in rescue mode

then I tried to see what is in the Fedora Provided initramfs :

zcat /boot/initrd-2.6.15-1.2054_FC5.img | cpio -i

Looking at the init script, panic is happening at the last stage, ie invokation of switchroot.
So the problem is probably related to the no fstab.sys message.
Great !
How can i generate this fstab.sys ?

[C6_bandini]

up
initramfs switchroot or my /sbin/init is leading to a panic.
any ideas ?