Comment 1 for bug 106339

For what it's worth, 2.6.20-15-386 shows exactly the same behaviour,
it hangs as soon as the "ubuntu"-splash screen is displayed. I have not
been able to convince it to display any boot messages.

2.6.20-13-386 is the last kernel that boots on my machine, some specs:

  pci.subsys_product = 'GA-K8N Ultra-9 Mainboard' (string)
  pci.subsys_vendor = 'Giga-byte Technology' (string)

00:00.0 Memory controller: nVidia Corporation CK804 Memory Controller (rev a3)
00:01.0 ISA bridge: nVidia Corporation CK804 ISA Bridge (rev a3)
00:01.1 SMBus: nVidia Corporation CK804 SMBus (rev a2)
00:02.0 USB Controller: nVidia Corporation CK804 USB Controller (rev a2)
00:02.1 USB Controller: nVidia Corporation CK804 USB Controller (rev a3)
00:04.0 Multimedia audio controller: nVidia Corporation CK804 AC'97 Audio Controller (rev a2)
00:06.0 IDE interface: nVidia Corporation CK804 IDE (rev a2)
00:07.0 IDE interface: nVidia Corporation CK804 Serial ATA Controller (rev a3)
00:08.0 IDE interface: nVidia Corporation CK804 Serial ATA Controller (rev a3)
00:09.0 PCI bridge: nVidia Corporation CK804 PCI Bridge (rev a2)
00:0a.0 Bridge: nVidia Corporation CK804 Ethernet Controller (rev a3)
00:0b.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
00:0c.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
00:0d.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
00:0e.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
01:0a.0 FireWire (IEEE 1394): Texas Instruments TSB82AA2 IEEE-1394b Link Layer Controller (rev 01)
02:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8053 PCI-E Gigabit Ethernet Controller (rev 19)
05:00.0 VGA compatible controller: nVidia Corporation NV43 [GeForce 6600] (rev a2)