Downgrading Kindle PW3 on 5.8.9.2?

[dhdurgee]

Originally Posted by Cinisajoy

I can guarantee it won't be me. The closest I come to an electronic anything is the month I spent learning to repair old video games back in the early 90's. Fun to learn but a paycheck would have been nicer.

Nor me. Perhaps we could find an interested EE prof that could make it a project for a research paper and give the interested students access to the research lab.

Alternatively, perhaps one of Amazon's competitors will tell us if we ask nicely. I am sure they have obtained units and reverse-engineered them as input to their development teams for their responses to Amazon's offering.

Dave

[favero_]

Hey, I was just wondering... Now that there's version 5.8.10, is it possible to "trick" the system into believing that the downgrade file (the 5.7.4 if I'm not mistaken) is actually the 5.8.10?

Me trying to be a smartass and with no knowledge of Programming tried to rename the downgrade file as the one for the update. Of course it didn't work, the Update my kindle was still grayed out.

But maybe a programmer can discover what makes the OS to accept the update file and erase an old one?

Anyway, just an idea...

[Cinisajoy]

Originally Posted by favero_

Hey, I was just wondering... Now that there's version 5.8.10, is it possible to "trick" the system into believing that the downgrade file (the 5.7.4 if I'm not mistaken) is actually the 5.8.10?

Me trying to be a smartass and with no knowledge of Programming tried to rename the downgrade file as the one for the update. Of course it didn't work, the Update my kindle was still grayed out.

But maybe a programmer can discover what makes the OS to accept the update file and erase an old one?

Anyway, just an idea...

Same answer. The cell doors are still locked.
Only if you had the keys (jailbreak installed) before it updated can you downgrade.

[knc1]

Originally Posted by favero_

- - - - -
But maybe a programmer can discover what makes the OS to accept the update file and erase an old one?

Anyway, just an idea...

You don't have to be a programmer to find out, just a little bit of background and your favorite binary display/edit tool.

*nix systems (of which Linux is one) do not recognize file types (or mime types) by the filename extension.
They use a system of what is called "Magic Numbers".

Download one of the factory initial packages -
Download one of Amazon's customer update packages -
Look at the value of the first four bytes of each (they are printable characters).
See?

The firmwares that will not install the 'factory initial' packages have had that package type disallowed.

And no, you can't just edit the package type, it is not the only 'marker' the file has in its internal structure, just the one that can be tested very quickly.

Like any other four letter word (click the link in my signature for a description of four letter words).

[favero_]

Originally Posted by knc1

You don't have to be a programmer to find out, just a little bit of background and your favorite binary display/edit tool.

*nix systems (of which Linux is one) do not recognize file types (or mime types) by the filename extension.
They use a system of what is called "Magic Numbers".

Download one of the factory initial packages -
Download one of Amazon's customer update packages -
Look at the value of the first four bytes of each (they are printable characters).
See?

The firmwares that will not install the 'factory initial' packages have had that package type disallowed.

And no, you can't just edit the package type, it is not the only 'marker' the file has in its internal structure, just the one that can be tested very quickly.

Like any other four letter word (click the link in my signature for a description of four letter words).

Thanks for the explanation!