Boot sequence

[Firefox]

Just a recap of the Keg boot sequence described in PN forums by Ryan.

http://www.phatnoise.com/forum/showthread.php?s=&threadid=2362

"Standard PhatBox Operation:

When it first gets power, it boots of off protected non-HU specific firmware (that never gets reprogrammed) and then turns off if there is no firmware update on the DMS (this prevents it from becoming a doorstop if it gets programmed with bad firmware).

After it turns off, it is running HU specific firmware and should be talking to the HU. When it gets ignition, it will boot the Linux processor.

The red light shows power to the Linux processor. The green light shows HDD activity and custom status "messages".

If the lights don't come on at all with ignition, that simply means that the microcontroller is not getting the ignition signal. In this case it is a bad cable or a bad connection. Make sure the hex screws are all the way in before screwing the cable into the PhatBox (or the cable could possibly be connecting power, but not ignition)."

[Firefox]

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Facts:
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8051 = microcontroller
ARM = linux processor

"something" handles the initial boot and firmware updates (and probably the "DMS-bless" check) before turning off.

this "something" is common to all PB/Keg (except Red and maybe early BMW) and cannot be reprogrammed via the DMS

a microcontroller (probably 8051) stays active after boot and runs headunit specific firmware which can be reprogrammed via the DMS.

when this "headunit microcontroller" gets an ignition signal it boots the Linux (ARM) processor.

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Questions:
- what is handling the initial boot?
- are there two 8051s in the PB/Keg?
- has anyone made a list of visible components inside a Keg/PB? even a picture would help!

Bummer:
If we are sure that the initial (protected) boot does the bless-check then we can never change that and we are back to original idea of discovering a way to bless our own drives.

Any comments?

[sbingner]

here's a picture of the circuit board in a 710... http://ns3.bingner.com/phatnoise/phatbox.jpg

Sam