Understanding JCOP: memory dump

Some time ago I was struggling with JCOP smart card. The one I received as it turned out was not pre-personalized, which means some interesting features (like setting encryption keys and PIN) was still unlocked. Because documentation and all the usual helpers (StackOverflow) were not very useful (well, ok, there was no publicly available documentation at all), I started very deep search on Google, which finished with full success. I was able to make dump of whole memory available during pre-personalization.

Since it is not something that could be found online, here you have screenshot of it, colored a bit with help of my hdcb program. Without documentation it might not be very useful, but in some emergency situation, maybe somebody will need it.

JCOP memory dump made at the very beginning of pre-personalization

Small explanation: first address, I was able to read was 0xC000F0, first address with read error after configuration area was 0xC09600. I know that, despite of lack of privileges some data is placed there.

There are three configurations: cold start (0xc00123-0xc00145), warm start (0xc00146-0xc00168) and contactless (0xc00169-at least 0xc0016f). Description of coding of the individual fields is outside of the scope of this article. I hope, I will describe them in future.

Next time, I will try to describe the process of pre-personalization, that is making not pre-personalized card, easy to get from usual sources of cheap electronics, able to receive and run applets.

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Airlive WN-151ARM UART pinout & root access


Airlive WN-151ARM pinout

For curious ones. Here is pinout of serial connection. As you can see UART pins are at J4 header (should have pin 4 labeled and 1 be square).

J4 header
Num. Function
2 RX
3 TX

Edit: Oh, and one more thing: goldpin header, you see in the picture is soldered by me, so do not be surprised if you have to hold wires all the time during the transmission.

Root access

There is also possibility to gain root access without removing the cover and possibly voiding the warranty. You have to connect to router’s AP and enter

into your browser (panel authentication required). Now you can execute any command you want with root privileges! So let’s type

/usr/sbin/utelnetd -d &

into Console command field and press Execute button. If everything went well, you should now be able to connect to your router using telnet at its default TCP port 23. After that you should see BusyBox banner and command prompt.

It is worth noting that this hidden console cannot be accessed by unauthorized person, so only router administrator can use this (in theory, in practice there are surely a lot of routers using default credentials and security of httpd binary is unknown).

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TP-Link TD-W8901G UART pinout

Some people might wonder: what is the pinout of my router’s serial connection. If you’re a happy owner of TP-Link TD-W8901G and asking that yourself, here is the answer:

TP-Link TD-W8901G's pinout

TP-Link TD-W8901G’s pinout

In the link below there is also this router’s pinout and moreover author states that to make that port working there is a need to modify some resistors. I have V3.5 of that router and didn’t notice any mod to be necessary.

It is possible to solder goldpins in here and router so far haven’t fried. Of course you can try communicating without stable connection and it even works but after training your fingers while waiting for the firmware download/upload to complete you’ll change your mind, I guarantee:).

PS: that model is the one that was one of the victims of massive DNS changing some time ago so if this is the one you’re using as your bridge to the Internet you may be also interested in this.

PS2: if you have another router and want to find out what is the serial port pinout I recommend going here.

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Graphic LCD based on ST7565 chip under Raspberry Pi

Hi, today I’d like to show you how to connect and use gLCD module with Raspberry Pi as host. The display I have is only bare display without any board not like the one in Adafruit’s offer. It can be powered by 3V3 Raspberry but the display itself needs a bit more power so we will need a few capacitors to build a circuit for that purpose. It will also make the connection a bit complicated (can be seen in the photo on the right). Nevertheless I think that the process is still rather easy.


Connected display

Connected display

As far as I know ST7565 based displays can be connected on two ways: parallel and serial. In case of serial connection, which I used to save few GPIO’s, it is possible to program it using SPI or just only GPIO’s. The display that I have is a bit different than most of the others because it has external backlight, which is additionally single LED so it is very power-saving (15mA). The only problem with that backlight was that the vendor didn’t told anything about parameters of that diode so I needed to figure it out myself.. The second problem while connecting the display itself might be amount of cables that need to be connected when using breadboard. Despite these two facts the whole process should be easy.

Physical connections

Connection scheme

Connection scheme

As said before the only step that may be a bit complicated is connecting so called step-up voltage circuit, made of 4 capacitors. The capacitors that we will use are 1uF electrolytic caps. Beside that we need to use another 5 caps (same as before) to connect parallel inputs to ground. So in sum we need 9 of them. Now we only need to connect VDD to 3V3 pin on Raspberry, ground from the schematic on the right with GND pin, SDATA to SMOSI on Pi, SCLK to SCLK and A0, RST and CS to any free GPIO. It is good to remember their numbers cause we will need it in a moment 🙂 It is important to use numbers used by Linux kernel, not wiringPi which has its own names. At last we need to connect the backlight. As said I have ECO backlight so I had to connect mine using 10 Ohm resistor. You can connect it to 3V3 or if you like to have control during runtime use GPIO, just like any other LED.

Configuring the program

Now I have to mention something about a program itself, because depending on how your vendor implemented the things your display will almost surely need a bit different settings. General procedure will look the same on every ST7565-based display. Main differences will be on particular commands during setup procedure.

uint8_t init()
  if (!bcm2835_init()) {
    return 0;
  bcm2835_gpio_fsel(LCD_BACK,BCM2835_GPIO_FSEL_OUTP);		//backlight
  bcm2835_gpio_fsel(LCD_A0,BCM2835_GPIO_FSEL_OUTP);		//A0
  bcm2835_gpio_fsel(LCD_RST,BCM2835_GPIO_FSEL_OUTP);		//RST
  bcm2835_gpio_fsel(LCD_CS,BCM2835_GPIO_FSEL_OUTP);		//CS
  bcm2835_gpio_write(LCD_CS,HIGH);				//set CS to high to indicate the bus as free
  bcm2835_gpio_write(LCD_RST,HIGH);				//hardware reset
  //setup SPI
  bcm2835_spi_chipSelect(BCM2835_SPI_CS_NONE);			//manual CS control
  bcm2835_spi_setClockDivider(BCM2835_SPI_CLOCK_DIVIDER_4);	//set speed to 62.5MHz (fastest supported)
  int i;
  for(i = 0; i < sizeof(initcmd)/sizeof(uint8_t); i++)
  bcm2835_gpio_write(LCD_BACK,HIGH);				//turn backlight on
  return 1;

I think that the code above should be generally clear. The most important for us is for loop that is executing every byte from initcmd array. Its content will look like that:

const uint8_t initcmd[] = 
  0xa1,							//screen orientation
  0x41,							//set starting line
  0xc0,							//page count direction
  0xa3,							//1/7 bias
  0x2c,							//vc
  0x2e,							//vc+vr
  0x2f,							//vc+vr+vf
  0x24,							//voltage regulator (0x20-0x27)
  0xa6,							//do not reverse the display
  0xaf,							//display on
  0xa4,							//display from ram
  0x81,							//turn on brightness regulation
  0x18							//set brightness (0x0-0x40)

The most important values here are:

  • voltage regulator – 0x20 means the darkest, as seen above in my case 0x24 worked
  • bias – I saw displays that had 1/9 so you need to make sure how is in yours and set it according to chips documentation linked at the end

You may also want to play with commands like screen orientation, page direction, display reverse or brightness to fit them to your needs. Now you have tell the program which GPIO you used as backlight (if you weren’t using GPIO you will now need to comment out few lines that sets backlight up), CS, RST and A0.

The program itself

To compile the program you will need to use external library named libbcm2835. It can be installed on ArchLinux ARM by issuing pacman -S libbcm2835 as root. If you are ready you can compile the program by typing: gcc -o lcd lcd.c -lbcm2835 assuming you didn’t change the filename. The simple program I’ve written, basing on the one posted on Gist by tmeissner here and ST7565’s documentation supports transferring single byte (commands too), whole framebuffer, or writing 5×8 single ASCII character or character string. Basing on both codes: mine and Meissner’s I think it is possible to do anything you could think about with that display.

Font creation

Standard ASCII table and traditional 'Hello World!':)

Standard ASCII table and traditional ‘Hello World!’:)

Ending slowly it’s time to tell something about fonts. As I said it is possible to simply write characters on the screen. To understand how all that thing works you need to know how the pixels are transfered to the display. The best explanation of the ST7565 display’s work can be in my opinion found here. TL;DR: the whole pixel space is divided into eight, 8-pixel high, horizontal pages divided into 128 columns that are 8 pixels high. If you didn’t understand, try link above. Nevertheless single letter is 8-pixel high and 5-pixel long so we need 5 bytes to store one letter. Its pixel map starts at left, top corner so it’s our (0,0) point and setting LSBof the first byte lights highest pixel. The font that is available in the code is Fixed 5×8 if someone is curious, it’s one of the default fonts in Xorg. To speed up conversion of the font to the display’s format I made simple OpenGL program to do the job for me. The code is of course available to download (check out my github).


Traditionally, at last some downloads:

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