Troubleshooting an unbootable A2


In some rare circumstances, customers have reported that the 'stock' A2 image does not boot on particular hardware. The symptoms are a blank, black boot screen that never proceeds.


Fortunately, this can usually be solved by providing the proper boot parameters to the A2 so that it can disable/enable the appropriate support for your hardware configuration.


Please note:

This fix does require Quadric technical support to remotely configure your A2 to make the changes permanent. However, you must determine which options are necessary to use in your particular case (see options below).


Manual steps to edit the A2's boot parameters:

-Boot A2 and IMMEDIATELY press F12 for the GRUB menu (you must be quick)

-Choose the first option and press 'e' to edit

-Scroll down to the line that starts with 'linux' and remove the word 'quiet'

-Add any desired additional boot parameters with spaces between at the end of the line.

A good place to start might be adding the following (without quotes):

"EDD=on nolacpi"

-Press "Ctrl-x" when finished editing to boot with the temporary flags


With luck, your A2 will now boot on your hardware, and eventually come to the A2 console menu screen.

At this point, you can now add your remote support code (provided by tech support) to allow a Quadric Engineer to remotely configure 

your changes to be permanent.




BOOT OPTIONS

nolapic

edd=on

acpi=off

noapic

nodmraid

nomodeset


nolapic

Very similar to noapic, but disables a different (newer) kind of APIC called a LAPIC(Local Advanced Programmable Interrupt Controller)


edd=on 

Enables the EDD probe(Enhanced Disk Drive), used by motherboards to provide more functionality to disk drives


acpi=off 

Disables ACPI which is used for power management and actually turning off power after the shutdown. This may help with compatibility with motherboards which misuse ACPI.


noapic 

Disables Advanced Programmable Interrupt Controller. This is used to resolve hardware conflicts for interrupts, but may itself cause a conflict. Use of this option may disable some hardware that enters a conflict without an APIC.


nodmraid

Disables dmraid which is used for RAID purposes but may cause empty disks to appear even if they are fully partitioned, possibly with the wrong size.


nomodeset 

Keeps the video driver from performing modesets which are used to bring the graphics card to an enhanced state, but due to incompatibility, may cause display issues.