Update eink waveform

[icecoldtony]

Originally Posted by Ian.M

Its pure luck if the waveform from the old screen matches the new one closely enough. Can you try swapping the screens (with the whole case front to minimise the risk of damage) over and see if the contrast problem follows the screen or the motherboard?

I have replaced the screens on two Kindle 3's. Mine and my daughters. I wish I had researched this before replacing and buying my first screen. After examining the screens I have determined the screen I bought for my Kindle has no Eprom chip. My daughters does. Both Kindles are wifi. I threw the old screen for my Kindle away. When my daughters screen broke I kept her old one to give to her. I have used her old screen to hot swop both Kindles. It's worked on both. Graphics display fine on both after how swopping. Trouble is my Kindle will remain stable for only a few days and will then reboot. Text always displays fine on both. I almost bought a used Kindle screen but for a few more dollars I could get new. Like I said, wish I had researched this earlier.

[predykat]

Hello,

I fixed thousands of kindles. Problem with WF occurs when kindle cant read eeprom during startup procedure. As i observed, its possible to use any e-ink screen (even sce - without eeprom) if eeprom was read prior to connect new screen. But problem is that there are some critical values (in eprom) like v-com voltage and physical characteristics of display. For amateur (end user/ owner) purposes using your old WF data will be enough. You can observe various errors like ghosting, screen become dark grey, some gray area are too dark or too light, there can be some artefacts on screen (for example when cursor or underline is moving)
But all this thing are unacceptable when you want to sell used product as 100% working.

E-ink corp sells various different types of sc7 screen:

c1 h1 h2 h3 h3-0B

However, i cant find info about differences. What i know, that C1 and H3-0B works with kindle normally, buy h1, h2, h3 makes troubles.

Since buying C1 or H3-0B is almost impossible, i tried to find solution:

1. Reprogram content of eeprom with working / similar content
2. Replacing eepom chip itself (from broken screen)
3. Program kindle permanently to use one, matched waveform instead reading every startup (like kindle 2 or dx, they dont have chip at ribbon)
4. Learn kindle how to use h1, h2 h3 map (WF data), because its little different, maybe lab126 will make some social job...

There are several screens, they works, but i cant match proper WF data, many, many tries.

So i can share some experience about doing it right (4)
Maybe we can make patch (update)


Sources:

PDF for ED060SC7 you can find here:

pdr for controler (older) is here

pdf for controller (newer) is here


And one more interesting document:

predykat at gmail

[HarryT]

Are you saying that you can fix any Kindle such that it will remember the waveform data correctly following a reboot?

[knc1]

Originally Posted by HarryT

Are you saying that you can fix any Kindle such that it will remember the waveform data correctly following a reboot?

I think the poster said that it might be possible.

Conditions:
1) Have waveform data that works with the screen.
2) Modify the system to use the waveform data store elsewhere than on the cable prom (some early Kindle models did not have a cable prom).
3) Find a place to store the waveform data (there may be room on the main flash, outside of the partitioned areas, for the 128Kbyte file).

Problems:
On (1) - waveform data files for some models of the screens has not yet been determined.

On (2) - Find where the hardware is initially programmed:
A) If in u-boot - we may be able to change that, we know how to replace u-boot.
B) If in the kernel's initramfs system - that one is signed, we have not tackled the chore of changing those contents.
C) If in the kernel's run-time system - that one we have been bending out of shape for years.

On (3) - That one is the easiest to do, those areas are pretty well known here.

@HarryT: At least the above is my reading of the post and the linked engineering documents are good background information.
There is no shortage of engineering skills among our members here, but I still wouldn't hold my breath, waiting for someone to solve this challenge.

[HarryT]

Originally Posted by knc1

I think the poster said that it might be possible.

That would be the "Holy Grail" of screen replacement, but I've never heard of anyone achieving it unless their replacement screen is - purely by coincidence - a good match for the waveform data that the original screen had. All the other solutions only work until the Kindle's rebooted.

[Ian.M]

A quick browse through the linked screen controller datasheets indicates the controller *CAN* be persuaded to permit write access to a blank SPI FLASH chip on the display cable. Digging into the code for the Update EINK waveform option of the diags mode would probably provide enough info to write a standalone utility to read and write the SPI FLASH waveform data without checking the screen's model code. As a safety feature, I would suggest requiring the exact model code to be entered for write if it is non-blank.

[stysis]

I had the exact problem described by Zirowe at the start of this thread and was looking for a solution and came across what seems to be the best option so far from tccsargent posted 09-21-2013.

When I first came across it I was reluctant to try it for 3 reasons: I had hastily thrown out my old cracked screen; it wasn't a major problem as I could still read books, only images were corrupted; and I didn't want to have to reinstall the hacks I had so much fun with after a factory reset.

Originally Posted by tccsargent

(2) While the Kindle is still open, attach the new screen to it and navigate to "Reset to Factory Defaults" in the system submenu of the Kindle, and press Enter.

But then I got thinking... If a restart will bring back the bad waveform, why wouldn't a restart install the good waveform?

So I opened my sons Kindle to try this with his screen and bingo! it worked beautifully.

A simple restart rather than a factory reset did the job for me.

Thanks to all whose wisdom I have benefited from. I've been having lots of fun with my Kindle 3 over the last few days, learning heaps from this wonderful forum about how it works and what can be done with it.

Cheers.

[knc1]

Seems obvious in hindsight.
Nice find.

[predykat]

i will conect kindle and look for default wf file. Somebody previously says that h3 flash was empty?

Simon

[montalex]

Just a tip for changing screens. You don't have to remove the battery (and thus lose the stored waveform) when changing screens. If you disconnect only the screen ribbon cable, and remove all black screws and only the silver screws around the perimeter (no need to remove battery, 3G module of the inner screws for the powered hinge contact), then you can lift out the motherboard and midboard together to change the screen. I just did it in less than 15 minutes, and the replacement screen (A Sony touch screen!) works and looks fine. No need to switch screens for a restart to store the waveform.

[gatolt]

Found very interesting article how to program Waveforms:
http://wenku.baidu.com/view/187d5395...5f465e245.html
Can't say that understood a lot but for those who does should be usefull...

[stysis]

When I read Nephiel's post describing how he copied waveforms to new screens I was determined to give it a go.

I've done it in much the same way but with some different techniques which I thought I'd share here.

The biggest difference was that I used a Raspberry Pi rather than an Arduino. There is a very clear guide to flashing chips with a Raspberry Pi here.

The other key difference was my method for connecting to the chip on the Kindle screen. Nephiel must have more dextrous fingers and better eyesight than me, I couldn't get the sewing pins to sit where I wanted them.

So I had to come up with something less fiddly. I had some long headers lying around and after a bit of bending of legs and some scraps of wood to make a jig, I had a more secure set up.

The 150R resistors described in the Raspberry Pi guide were not needed (I didn't have any 150R so tried 220R and got no result, so I took them out). There is also no need to make the connection to pins 3 and 7 of the chip. Connecting the flash chip is also described in the Flashrom web site here.

When you connect a new screen don't assume the rom chip is blank. Make sure you read the chip as a first step before erasing or writing. I've looked at 2 new screens bought on ebay, one had a perfectly good waveform file which I now have a copy of.

Happy flashing!


One of the headers used to connect to the chip.


The mocked up jig with screws clamping the chip and headers in place. (The extra 2 headers are just there to make the wooden clamp sit flat.)


Close up of the headers in contact with the chip. Pin 1 is at the bottom left. Note that pins 3 and 7 are not connected.


The whole set up.

[knc1]

Nice solution.

Also glad to learn I am not the only one who finds this new stuff "too small" to see and work with.

[Nephiel]

Nice work, stysis!

Could you attach to your post a copy of the eeproms you have? I think it would be helpful to have more publicly available, in case one doesn't have the right waveform for a given panel.

[knc1]

Originally Posted by Nephiel

Nice work, stysis!

Could you attach to your post a copy of the eeproms you have? I think it would be helpful to have more publicly available, in case one doesn't have the right waveform for a given panel.

Probably not a good idea to do that before determining Copyright ownership.

MR does not allow posting of copyrighted materials without the permission of the copyright holder.