FlashROM and RAM

The memory.
I have not looked up the part numbers, yet, so this is purely a guess...

The four ICs on the right are FlashROM. The Digibox firmware (which can be 'downloaded' from the satellite) comes to approximately 1.6Mb. Thus, it would be logical to assume 2Mb of FlashROM; in four 512K parts. Update: I have found an unofficial source that claims there is 4Mb of FlashROM inside the average Digibox.

We know that we need to have at least 2Mb of RAM in order to hold a copy of the image to commit to FlashROM during an upgrade. Actually, it is more complex as the data downloaded from the satellite is approximately 950K, a compressed FlashROM image. I guess it works out faster to decompress a small image than to download a larger one... It is entirely possible to decompress 950K to 1.6Mb within 2Mb of RAM, but it is much simpler within 4Mb of RAM; and it also seems that a typical specification is for 4Mb, so until we know better, shall we assume that we have 4Mb of RAM? Okay... Update: The unofficial source agrees with this guess.

There is one final thing. Apparently the Digibox contains a 128K "bootloader", this is likely to perform a basic self-test and get everything initialised and ready to begin the software held on FlashROM. It is also possible that this bootloader contains a form of BIOS so similar models can use the same FlashROM code, with the bootloader's BIOS taking care of the little differences. This is borne out by the FlashROM image that I have obtained, apparently for the BSkyB 2500B, containing references to the Sky+. This never appears on my box as it isn't a Sky+...
The position of the bootloader ROM? I would guess the IC upper middle, slightly cut off in this picture.

 

In order to work correctly, the receiver will need to have the latest firmware installed. This was broadcast in January and February 2006. Most receivers will have been updated, with the following known exceptions:

Without the latest firmware, the box may (GDS200 yes, iDTV unknown): and in both cases, the EPG listings will not show any radio channels. These have '0xxx' numbers and the EPG installed will not be able to recognise nor list them.

In short, if you are offered one of these devices for free, you might as well take it to play with.
If you are considering paying for one of them... don't!

 


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Copyright © 2006 Richard Murray