PW4 Hardware Mod Discussion

[Junket]

Originally Posted by AbdulHamdy

I'm not feeling particularly confident that the reader will enumerate when it's connected..

The test I would do before tearing your Kindle apart is connect your OTG adapter and USB SD-card reader to the existing external USB port. You should be golden if that works.

I don't see why it wouldn't enumerate as a simple storage volume, and the one of the early Kindles actually had an SD card mounted. The functionality should already be there unless you use a really oddball or esoteric reader. Common models are almost universally supported by linux and Amazon OS is a variant on that.

You are using an existing USB port pinout (intended for a 3G modem) to OTG adapter to USB SD-card reader. Or an USB hub if you need to support more than one USB port. Geekmaster made at least one post delving into the latter.

[trcm]

The iMX are capable of muxing almost all their BGA pads for the functions available, so USB pads or UARTs can be in surprising places. One must examine the device tree blobs which define what appears where. They’re probably stored in their own partition somewhere.

Took me forever to find the correct UART (1 of 4!) for the board I was playing with (https://www.axiom-partners.com/ilx702d)

[NiLuJe]

If that's what I think it means, in addition to that (because I don't think I know where they are tucked away on Kindle) they're shipped with FW updates and/or are available in the kernel sources.

Fair warning: not a HW guy ^^.

[trcm]

If they’re freely available in the fw updates then you’re well on your way to mapping out the likely traces you want to play with. And you’ll also know what features are ‘enabled’.

[knc1]

Originally Posted by trcm

The iMX are capable of muxing almost all their BGA pads for the functions available, so USB pads or UARTs can be in surprising places. One must examine the device tree blobs which define what appears where. They’re probably stored in their own partition somewhere.

Took me forever to find the correct UART (1 of 4!) for the board I was playing with (www.axiom-partners.com/ilx702d)

And the device tree source should be included with the Linux kernel's source in each model/firmware combination that Amazon releases. **

Ref:
https://www.amazon.com/gp/help/customer/display.html/ref=help_search_1-1?ie=UTF8&nodeId=200203720&qid=1581121656&sr=1-1

Note:
There are update*.bin files for each of those model/version number combinations still on the Amazon server.

See:
Frequently Asked Questions (here, this forum)

** There have been various exceptions to that "rule", but what else are rules for?

[Junket]

NXP provides a "pins tool" app to configure which physical pad an given output is routed to.

The app generates a set of register values. Each output has an unique and fixed label that may yield to a string search in the source. Some of register values set are also unique which present another string to look for.

[trcm]

Not sure you’ll benefit from knowing the register values, the device tree file names the actual pads.

[AbdulHamdy]

Originally Posted by knc1

IIRC, the PW4 is a dual core device.


If you don't have 4G, then you do have a spare USB port on-board. You should be able to find those threads (on earlier models). At least one of them had added a hub using the 3G port.


The PW4 already supports OTG with both hardware and firmware.


geekmaster has posted threads and details of experimenting with the various remote file systems and remote file system hardwares. Again, older models, but Linux is still Linux.

Can you or somebody please find me that information ? I cannot find it, I have searched and exhausted reasonable time trying to. Any help would be appreciated.

I think that the internal port would more ideal to preserve the external port as-is for file transfers with a closed case to retain the waterproofing. Obviously, Using the external port would be that much easier.. But a little effort spent now for a more streamlined experience makes more sense.


@trcm Have you documented the search for the UART ? I'm sure I could learn a thing or two from your experience and methodology

[trcm]

Only what is on that website, the methodology was use the device tree to produce an overlay of where the likely pads lay, then probe all the traces emanating from that edge of the BGA chip.

[ydi]

Originally Posted by knc1

And the device tree source should be included with the Linux kernel's source in each model/firmware combination that Amazon releases. **

Ref:
https://www.amazon.com/gp/help/customer/display.html/ref=help_search_1-1?ie=UTF8&nodeId=200203720&qid=1581121656&sr=1-1

The product names Amazon uses in this list does not look the same as the one in
eg. https://wiki.mobileread.com/wiki/Kindle_Serial_Numbers ? Which one of the Amazon
model names would be the PW4 ?

[j.p.s]

Originally Posted by ydi

The product names Amazon uses in this list does not look the same as the one in
eg. https://wiki.mobileread.com/wiki/Kindle_Serial_Numbers ? Which one of the Amazon
model names would be the PW4 ?

One of the reasons that wiki page exists is because Amazon model names are a muddle.

The PW4 is the model that amazon is currently selling new as the paperwhite.

Before the PW4 was announced, amazon was selling the PW3 as the paperwhite.

The PW3 and PW4 are very different.

[ydi]

Originally Posted by j.p.s

One of the reasons that wiki page exists is because Amazon model names are a muddle.

The PW4 is the model that amazon is currently selling new as the paperwhite.

Before the PW4 was announced, amazon was selling the PW3 as the paperwhite.

The PW3 and PW4 are very different.

OK, so PW4 == "Kindle Paperwhite (10th Generation)", or is there anything more subte about those "generations" ?

[Junket]

Chiefly that the file system is quite different in the PW4, using an android-type file system, rather than the previous diag/main dual boot.

And then a plethora of smaller differences such as memory capacity, conformal coating (waterproof) and so forth.

PW3 (2015 /7th gen)
PW4 (2018 /10th gen)

[knc1]

Originally Posted by ydi

The product names Amazon uses in this list does not look the same as the one in
eg. https://wiki.mobileread.com/wiki/Kindle_Serial_Numbers ? Which one of the Amazon
model names would be the PW4 ?

Since we do not list the PW5, since it does not (yet) exist, then the most recent Paperwhite that Amazon is selling/listing must be what we call the PW4.


For a better answer, see above post.

[ydi]

It could be useful to add those "official amazon names" as a column in https://wiki.mobileread.com/wiki/Kindle_Serial_Numbers, and rename the current "Model Name" column to something like "Community Model Name" or something similar, right ?