i've got exactly the same problem on a Compaq Deskpro EN 6400/6.4.
It must be a Compaq BIOS problem?
I have already noticed this qeury on linuxquestions.org, but there was not an answer to this.
I try booting Knoppix from CD on my Compaq Armada 7400 laptop, but not successful, the CD is found, SYSLINUX is started, but then boot process halts (I can see the message SYSLINUX DEBIAN 2.04 (Debian, 2003-06-06) followed by a bunch of garbage symbols). When I boot Knoppix from diskette using the same CD, the system loads without any problem. Another hint is that I can boot the system from the same CD on another laptop Compaq Evo N600c.
Appreciate every advice.
i've got exactly the same problem on a Compaq Deskpro EN 6400/6.4.
It must be a Compaq BIOS problem?
CISCO MCS 7800 (2x) Intel Xeon @ 2.33 GHz 4GB Ram, NO HDD
$44.99
$599.99
$80.00
Dell Precision T3600 | Xeon E5 | 16GB | GPU | 128GB SSD | Win 10 Pro
$115.00
Intel SR2JT Xeon E5-2683 v4 2.10GHz 16-Core CPU Processor
$21.96
Intel Xeon E5-2680 v4 2.4GHz 35MB 14-Core 120W LGA2011-3 SR2N7
$17.99
Intel Xeon Gold 6140 SR3AX 2.3GHz 18-Core Processor CPU
$39.99
Intel Xeon E5-2699v4 SR2JS 2.2GHz 22-Core 55MB 145W Server Processor CPU
$144.95
HP Workstation Z640 2x Xeon E5-2623V4 32GB Ram Dual 256GB SSD K420 Linux GA
$234.98
Dell Precision Tower 7910 | 2x Intel Xeon E5-2643 V3 | 32GB RAM | No HDD | No OS
$179.95