Return to original firmware

[marylou13]

Hello everyone! My device updated to 5.7.4 before I had the chance to jailbreak it. And I am looking for ways to downgrade it without opening the device.
My question is this:
Why Kubrick cannot work for installing the original firmware? (the one the device had on when shipped) I did a bit of searching through the forums and found that it won't apply to KT2.

Thanks!
M.

P.S: I am also subscribed here (thanks knc1!)

[geekmaster]

Originally Posted by marylou13

Hello everyone! My device updated to 5.7.4 before I had the chance to jailbreak it. And I am looking for ways to downgrade it without opening the device.
My question is this:
Why Kubrick cannot work for installing the original firmware? (the one the device had on when shipped) I did a bit of searching through the forums and found that it won't apply to KT2.

Thanks!
M.

P.S: I am also subscribed here (thanks knc1!)

Kubrick requires a device to be in USB Downloader mode, which is activated by holding down a physical button (i.e. a "magic key") on the device while powering it on. Devices newer than a K5 have no button to hold. However, most of them DO have internal pads (somewhere) that connect to the same BOOT0 and/or BOOT1 (USB boot mode) bins on the SoC device, but so far nobody has figured out how to use them AND it would still require opening the device to connect to those pads on the PCB. And while open, you might as well do the serial jailbreak that we DO understand. Amazon is NOT making it easy for us, and in fact is trying hard to NOT allow us to use our kindles in ways we prefer (by attacking our rights as owners of our own kindles).

TL;DR -- KT2 (and newer) devices lack a "magic key" required by Kubrick.

[marylou13]

Thanks for replying so fast!

Originally Posted by geekmaster

Kubrick requires a device to be in USB Downloader mode, which is activated by holding down a physical button (i.e. a "magic key") on the device while powering it on. Devices newer than a K5 have no button to hold.

I thought the magic key for that device was the power button. So if the KT2 is bricked what can you do? In the forum, it said that you should install a rescue pack in order to be safe when you start tinkering the device. There is a rescue pack for the KT2. Isn't there a way to use that initial file to sort of reset the device to factory settings?

[geekmaster]

Originally Posted by marylou13

Thanks for replying so fast!

I thought the magic key for that device was the power button. So if the KT2 is bricked what can you do? In the forum, it said that you should install a rescue pack in order to be safe when you start tinkering the device. There is a rescue pack for the KT2. Isn't there a way to use that initial file to sort of reset the device to factory settings?

You can flash firmware by using the serial port, but you need to open the device and attach wires to some tiny metal pads on the circuit board (usually by soldering them). And that is just the start of possible complications, so you need patience and some degree of skill to do it. That is why jailbreaks that only need a USB connection are preferred.

I am not aware of the power button being a kubrick-compatible magic key (but I have been away from these forums since before the KT2). If you can provide a link to such information, please do so. Thanks.

EDIT: I just noticed you link to knc1's post about firmware downgrades. That looks interesting -- I was not aware of that before. Thanks.

[knc1]

no time to do sufficient testing yet.

on one KV that we tried, it ruined the partitioning - - -
but that KV was already in serious trouble, so that testing was probably a waste of time.

[geekmaster]

My PW3 has a test pad labelled "JTAG" (though JTAG needs more wires than that), which indicates that there probably IS a JTAG port on that and compatible devices. JTAG is amazing if you know how to use it (my knowledge is rather limited). If we gain access to that, we are golden... But then we need a test-jig thingy...

[IFixKindles]

I'm not sure if this would work on yours or brick it. I had several PW1 which for some strange reason would register under 5.3.9, but not under later versions.

I was able to successfully downgrade the OS from 5.6.1.1 back to 5.3.9 by forcing it to update (downgrade) while still connected to the computer.

Attached to computer via USB. Transferred the 5.3.9 update bin file to the kindle.
DO NOT eject from computer. Instead, hold kindle power button until it goes into update mode. This skips the usual checking on disconnect that made sure you were not putting in an older update file than what was installed.

[geekmaster]

Originally Posted by IFixKindles

I'm not sure if this would work on yours or brick it. I had several PW1 which for some strange reason would register under 5.3.9, but not under later versions.

I was able to successfully downgrade the OS from 5.6.1.1 back to 5.3.9 by forcing it to update (downgrade) while still connected to the computer.

Attached to computer via USB. Transferred the 5.3.9 update bin file to the kindle.
DO NOT eject from computer. Instead, hold kindle power button until it goes into update mode. This skips the usual checking on disconnect that made sure you were not putting in an older update file than what was installed.

Great information. I did notice that newer kindles delete update files that fail their test on USB eject (and I saw in in installer scripts as well), but I did not know this can allow installing "obsolete" (i.e. hackable) firmware. Thanks! But of course, publishing it here means that lab126 will surely "fix" it (i.e. take away our ownership rights) soon.

[eschwartz]

This is a known workaround on certain firmwares.

The "downgrade attack" error check is in the ota updater, but not in the boot-time updater on (IIRC): pre-5.6.x firmware and the PW1.

[shamanNS]

They already "fixed" it for PW2 and newer. It PW1-only thing now.