[CentOS-devel] incorrect diskboot.img in CentOS 5.7 i386 dvd iso

Hello,
trying to make a usb install on a thin client it seems I notice an
incorrect diskboot.img image in 5.7.
Anyone already discovered/reported this?

As soon as I boot from usb pen drive, I get an error
Could not find kernel image: linux

this depends on syslinux.cfg being empty

sha1sum of my dvd iso is correct
# sha1sum CentOS-5.7-i386-bin-DVD-1of2.iso
e0eab4dd77c3ecc73080428beaa4ffe28984dc4b  CentOS-5.7-i386-bin-DVD-1of2.iso

# mount -o loop CentOS-5.7-i386-bin-DVD-1of2.iso /mnt/

# sha1sum /mnt/images/diskboot.img
0568258b34eda506e76801ea5bfd6b57cdd299bc  /mnt/images/diskboot.img

# mount -o loop /mnt/images/diskboot.img /pp

on CentOS 5.7
under /pp I have:
total 12244
-rwxr-xr-x. 1 root root      292 Sep  5 11:53 boot.msg
-rwxr-xr-x. 1 root root      919 Sep  5 11:53 general.msg
-rwxr-xr-x. 1 root root 10450542 Sep  5 11:53 initrd.img
-rwxr-xr-x. 1 root root    10648 Sep  5 11:53 isolinux.bin
-r-xr-xr-x. 1 root root     9660 Sep  5 11:53 LDLINUX.SYS
-rwxr-xr-x. 1 root root    94600 Sep  5 11:53 memtest
-rwxr-xr-x. 1 root root      817 Sep  5 11:53 options.msg
-rwxr-xr-x. 1 root root      517 Sep  5 11:53 param.msg
-rwxr-xr-x. 1 root root      490 Sep  5 11:53 rescue.msg
-rwxr-xr-x. 1 root root    63803 Sep  5 11:53 splash.lss
-rwxr-xr-x. 1 root root        0 Sep  5 11:53 syslinux.cfg
-rwxr-xr-x. 1 root root  1892352 Sep  5 11:53 vmlinuz

while on CentOS 5.6
total 9562
-rwxr-xr-x. 1 root root     292 Mar 29 23:15 boot.msg
-rwxr-xr-x. 1 root root     919 Mar 29 23:15 general.msg
-rwxr-xr-x. 1 root root 7705221 Mar 29 23:15 initrd.img
-rwxr-xr-x. 1 root root   10648 Mar 29 23:15 isolinux.bin
-r-xr-xr-x. 1 root root    9660 Mar 29 23:15 LDLINUX.SYS
-rwxr-xr-x. 1 root root   94600 Mar 29 23:15 memtest
-rwxr-xr-x. 1 root root     817 Mar 29 23:15 options.msg
-rwxr-xr-x. 1 root root     517 Mar 29 23:15 param.msg
-rwxr-xr-x. 1 root root     490 Mar 29 23:15 rescue.msg
-rwxr-xr-x. 1 root root   63803 Mar 29 23:15 splash.lss
-rwxr-xr-x. 1 root root     340 Mar 29 23:15 syslinux.cfg
-rwxr-xr-x. 1 root root 1888052 Mar 29 23:15 vmlinuz

Tried to simply copy the syslinux.cfg from 5.6 and recreating
diskboot.img but as soon as there are some dots of the initrd phase,
just before the moment when I should see the kernel messages the pc
reboots itself.
it is a Dell thin client Optiplex FX160
Donna if it could be a problem with my hw or other kind of problems in
necessary files.....

Gianluca