[Progress] Jailbreaking Kindle 4.0 (Touch/No Keyboard)

[geekmaster]

Originally Posted by yifanlu

.. shaved the edge of a credit card and tore this sucker apart ...

Another common substitute for a spudger is to use a guitar pick. No shaving needed.

[ramirami]

Originally Posted by geekmaster

@yifanlu: have you seen these photos yet:
http://www.anandtech.com/show/5159/a...ouch-3g-review

@ramirami: that device looks like it uses logic levels for 3.3v and 5v TTL (3.3v and 5v TTL use the same logic levels). Different logic levels are used for 2.5v and 1.8v TTL, like used in the newer kindles. It might still work, but no guarantees.

Yes but I want to know what happen in previous versions of kindle if you connected via serial , what did you see?

[geekmaster]

Here is a sample of what you see on the serial port during boot:
http://igorsk.blogspot.com/2007/12/kindle-boot-log.html

You can see a lot of that same information by typing a 'dmesg' command at a root prompt in the kindle (either USBnet telnet or ssh prompt, or Luigi's kindle terminal -- I prefer myts-6)...

The special thing about serial port access is that certain key presses sent over the serial port at the right time let you get into a diagnostic menu, where all the *real* magic happens.

[ramirami]

Originally Posted by geekmaster

Here is a sample of what you see on the serial port during boot:
http://igorsk.blogspot.com/2007/12/kindle-boot-log.html

You can see a lot of that same information by typing a 'dmesg' command at a root prompt in the kindle (either USBnet telnet or ssh prompt, or Luigi's kindle terminal -- I prefer myts-6)...

The special thing about serial port access is that certain key presses sent over the serial port at the right time let you get into a diagnostic menu, where all the *real* magic happens.

I just checked those three pins and it seems that the center and the right have V1.77 left is 0.
Can this indicate on something.
Also the RX term isn't on the circuit.

[geekmaster]

The 0v would be GND. If you connect an oscilloscope to the 1.8v TTL pins, one of them should have a series of pulses (ASCII data) while the kindle is booting up. You can hold the power button for about 7 seconds to power down, and another 30 seconds to reboot (or select Restart in the settings menu).

With no oscilloscope, you should see the average voltage drop a little (with an analog voltmeter) or fluctuate (with a digital voltmeter) during reboot.

The fluctuating pin is Tx (out of the kindle). The other pin is Rx (into the kindle). Be sure to connect the Tx from the adapter to Rx into the kindle and vice-versa, or they will not communicate.

Also, it is a good idea to use 1.8v TTL. You can convert the voltage levels like this:
https://www.mobileread.com/forums/sho...15&postcount=5

[yifanlu]

So, still looking for the name to that port...

[geekmaster]

Originally Posted by yifanlu

So, still looking for the name to that port...

I should think its name would be something like "1.8v TTL Serial Port".

Yes, I know you are interested in knowing the connector part number too...

You *could* just connect directly to the pins. I just now bought a 60-pack of these micro test clips on ebay for $16.07 (free shipping):
http://www.ebay.com/itm/130591786190

Of course, they are from China so it could be a month before they arrive. Such things are available locally but for prices more like $10 each. ;(

I just searched for more, sorted by distance from me, looking for a USA provider. The closest was from Hong Kong.

I discovered that I *could* have gotten 100 test clips for less than $15. Still, 60 is more than I need...

[ramirami]

Originally Posted by geekmaster

I should think its name would be something like "1.8v TTL Serial Port".

Yes, I know you are interested in knowing the connector part number too...

I'm working on how to connect it to my computer.
I will report you guys.

[ramirami]

geekmaster,
I need to drop from 5v to 1.8v is it possible to do it with 470k resistors (what i have)?

[geekmaster]

You can try it. 470K might only work for very slow data rates though. 10 of them in parallel would be 47K, and more likely to work at the speeds needed.

You can also "steal" resistors out of junk electronic devices. You would need to solder small wires on any salvaged surface mount resistors though. You can tell which "little boxes" are resistors by the "R" markings on the silkscreen printed solder mask. If you keep all the resistors separated from capacitors and such, you can just measure their resistance. Some people extract parts from circuit boards with a butane torch:
http://www.instructables.com/id/Salv...nt-components/

All you need is a common TTL "pull-up resistor". I suspect that MOST of the resistors on any digital circuit board would work as TTL pull-ups for the kindle serial port level conversion.

[geekmaster]

@yifanlu:

I found some similar test clips available from the US, so you could get them MUCH quicker. Instead of multiple colors like the Chinese ones, these are all grey:
http://www.ebay.com/itm/200535094436

The problem is, like other stuff made in America, a twenty pack is $45 (instead of a 100 pack of Chinese ones for $15). Of course, with all those donations rolling in, you can now AFFORD to "Buy American!"

[Serpentine]

Yeah it's a generic header, pretty sure I have one exactly the same on an old PSU, remember the shorter than expected pins.

http://www.serialstuff.com/products/...gic-Cable.html
I know the chip can do 1.8, tho it's generally only used for 3.3/5v, on similar cables. Nice having free connectors tho, if the headers pins are long enough, pretty sure they should be.

[geekmaster]

Or you can get a Nokia cell phone cable for $3 shipped off ebay (I did). Here are some details on how to use it:
http://hackaday.com/2010/02/25/nokia...l-in-disguise/

Or, these $4.30 computers come with USB serial, and you could tap the TTL serial off the board:
http://estore.ti.com/MSP-EXP430G2-MS...kit-P2031.aspx

[ramirami]

geekmaster, i want to use this chip (i have it) :

This is the datasheet of the chip
http://www.sparkfun.com/datasheets/IC/FT232R_v104.pdf

Please have a look at page 7.

By this information I need two levels of voltage 3.3V for Pin no. 20 to power up the circuit. and another voltage of 1.8V for Pin no. 4 for output levels.

Do you think it should work?

[geekmaster]

Originally Posted by ramirami

... By this information I need two levels of voltage 3.3V for Pin no. 20 to power up the circuit. and another voltage of 1.8V for Pin no. 4 for output levels.

Do you think it should work?

It looks like it should work. They recommend using voltage regulators to get the 3.3v and 1.8v.

A very simple non-critical low-current voltage regulator can be made from an LED (which acts as a zener diode) and a current-limiting resistor. Red LEDs have a forward voltage drop of 1.7v to 1.9v depending on their brightness rating. This range should be fine for the 1.8v needed. Other color LEDs such as green or blue (but not bright blue) have a forward voltage drop of 3.4v, which should be fine for the 3.3v supply. Or, two (not very bright) red LEDs in series would give about 3.4v, which should be okay too. You need to supply the LEDs with voltage from 5v or so (which you can get from the USB power pins) through a current-limiting resistor (1K to 10K is typical). A lower resistance gives higher brightness but uses more current and is not need for this application.

Read more about LED voltage drops here:
http://www.theledlight.com/LED101.html