SIEMENS / SAGEM Gigaset SX762 / SX763

20150409 zo0ok: When I cleaned up the ToH I thought about writing 2×333 in the CPU MHz column. But since it clearly stated in this article that the second core is for VOIP it is not clear that OpenWrt can use the second core in SMP fashion. Please clearify (and delete this note).

v1 is based on amazon SoC, so we won't talk about that version here.

Beware when buying a SX762 second hand, it might have the correct serial number, but the wrong firmware, see link above

• ADSL modem is working with both Annex A & Annex B supported.
• WiFi is working out of the box with trunk. (ath5k)
• FXS works and can be used with owsip daemon.
• USB works with a ugly patch.
• FXO port is not working.

→ Install OpenWrt (generic explanation)

Please check out the article flash.layout. It contains an example and a couple of explanations.

The original firmware contains two modified uboot bootloaders. Only the secondary one has a CLI.

• The primary bootloader checks the header checksum (sha256) of the secondary bootloader
• The secondary bootloader does the same thing with the firmware.
• The sha256bit header checksum is generated by a 1024bit RSA private key which is currently unavailable.

Since the checking is only done for first 64Bytes of every 64k block it is possible to edit the secondary bootloader because it's size is less than 64k, by replacing lzma part and replacing it with lzma compressed u-boot. You have two options to install OpenWrt:

If for any reason OpenWrt fails to boot, a recovery HTTP server can be started by keeping the reset button underneath pressed, while powering the router on. Note that original fw .img can't be uploaded via recovery HTTP server.

1. download a modified secondary bootloader here
2. The modified secondary u-boot bootloader can be flashed from original web interface firmware upgrade section
3. after replacing the original secondary bootloader over the original WebInterface with the version provided in the link, you need to reboot the device.
4. since there is no OpenWrt in flash yet, after a reboot it will open HTTP server on 192.168.1.1 (tho it might be some other IP, such as 192.168.2.1; it probably depends on the IP preset in your nvram) asking for OpenWrt image.

The secondary_boot.img in the link above has broken networking, it works on some browsers and doesn't on others, but one can try older firefox versions, or booting win xp, or old linux distros in wm... After flashing it uploading through the HTTP server won't work. You have to use the serial interface and UART method afterwards as described below.

This is used to flash u-boot as a primary bootloader. There are two methods to flash u-boot as a primary bootloader, first one from a runing openwrt image, and a second one from serial console

1. before replacing the bootloader, make sure that you flashed secondary bootloader as noted above and that you are running openwrt fw from here
2. obtain the replacement booloader by selecting it the buildmenu (configuration), or downlaod from snapshot
3. if you compiled u-boot you will find the file u-boot-bootstrap.bin in ../trunk/bin/uboot-lantiq-gigaSX76X_DDRsamsung166/ after compilation.
4. copy u-boot-bootstrap.bin to /tmp folder inside router filesystem.
5. flash env to uboot_env partition with “dd if=/dev/mtdblock3 of=/dev/mtdblock4”
6. flash u-boot-bootstrap.bin with “mtd write /tmp/u-boot-bootstrap.bin uboot”
7. now reboot, run recovery HTTP server, and flash image from trunk

For the second method you must have a serial TTL interface installed! You need also a TFTP server and new built u-boot-bootstrap.bin in its root folder.

1. U-boot CLI commands:

   setenv ipaddr 192.168.1.1
   setenv serverip 192.168.1.254
   
   //unprotect sectors
   protect off 1:0-20
   
   //first copy nvram to new address:
   era 0xb0010000 0xb001ffff
   cp.b 0xb000e000 0xb0010000 0x2000
   
   tftpboot 0x816e0000 u-boot-bootstrap.bin
   era 0xb0000000 0xb000ffff
   cp.b 0x816e0000 0xb0000000 0x10000
   reset

1. since there is no OpenWrt in flash yet, first time after reboot the bootloader will open HTTP server on 192.168.0.119 asking for OpenWrt image.

(Thanks to snk for supporting and make it work)
Since the bootloader for AA is broken and there are not yet any BB-ready images, this will give you a temporary installation for BB. All BB images needed for installation can be found here.
This procedure uses a tftp server on your system. See the Wiki for detailed information. Set the computers IP address to 192.168.1.2. This is the serverip from which the router loads the images.

Follow the next steps for installation

1. Download, sx762.img, sx762-fw.bin, u-boot.bin and place them into your tftp directory. The sx762-fw.bin contains the MAC address of your WIFI.
   Modify the bytes 22-27 (0x16-0x1b) of this file to contain your MAC address.
2. Download u-boot.asc and place it in your local home directory.
3. Set the router in UART mode and setup a serial link to your router (see below for detailed description).
4. Copy the file u-boot.asc from your local home directory to the router ( “cat u-boot.asc > /dev/ttyUSB0”) and wait until the transfer is completed
5. Because this bootloader is in RAM only we need to load the bootloader into ROM

   run update-uboot-nor

6. After this is completed we can powerdown the router and remove the UART strippings. Leave the serial connection in place!
7. Next power up the system and interrupt the bootproces with [space].
8. Now we load the firmware into flash

   tftp sx762_fw.bin
   protect off 0xb07f0000 +$filesize
   erase 0xb07f0000 +$filesize
   cp.b $fileaddr 0xb07f0000 $filesize
   protect on 0xb07f0000 +$filesize

9. Load the image into flash

   tftp sx762.img
   protect off $kernel_addr +$filesize
   erase $kernel_addr +$filesize
   cp.b $fileaddr $kernel_addr $filesize

10. Reboot with the command: [reset].
11. Enable wifi and off you go.

CPU info:

PCB:

Note: This will void your warranty!

To get to the board you need:

• unscrew 4 torx-10 screws underneath the cover,
• pull the upper cover which is connected by click.

→ port.serial.

Pinout:

If your serial cable requires a Vcc, you can use the lower-right pad (i.e. not the one just below the two GND pads, but the one below that).

Serial port is at 3.3V and the bitrate is 115200.

Serial output from default bootloader:

→ port.jtag general information about the JTAG port, JTAG cable, etc.

How to connect to the JTAG Port of this specific device:
Insert photo of PCB with markings for JTAG port

Bootstrap pin funcion table:

Value 1 = 3.3v is connected to that pin
Value 0 = Pin is connected to digital GND

boot_sel2, boot_sel1, boot_sel0 pins location:

Note: boot_sel2 and boot_sel1 are by default on 0 and boot_sel0 is on 1.

To enable uart mode, short pins at boot_sel2 (see picture) and connect boot_sel0 to gnd. Than you can send u-boot.asc(downlaod here) to serial port.
For example if your serial port is ttyUSB0 than do: “cat u-boot.asc > /dev/ttyUSB0” and wait until u-boot starts.

UART mode looks like this:

ROM VER: 1.0.3
CFG 04
Read EEPROMX
 X
UART

SX763 uses a DC/DC switching regulator for 5V USB power, and unfortunately the chip is disabled by OpenWrt and other unofficial firmware (as of april 2013). The chip that provides 5V for USB has enable pin (number 7 to be exact), and the original firmware pulls the enable pin from 0.3V to 3.3V about two seconds before the relay makes a click sound.

According to datasheet, enable pin can be unconnected if we want the chip to auto-start, and that is exactly what we want. Therefore, we just need to disconnect the pin number 7 and SX763 will have 5V at USB connector all the time.

Note: When sx76x support gets back to trunk, there will be usb power by default so this hack wont be needed.

A close-up:

Another close-up is available at : http://pljusak.com/papuk/RSCN1314.JPG

The good sides of this hack are: 1) if you break the pin on the chip no harm is done, and 2) there are no side-effects in possible overloading the other 5V regulator that is used if you bring the 5V from another DC/DC regulator, as in hack that follows.

Previous version of 5V-USB hack follows:

Here is example of added usb power (5.05V measured) over simple pin solder so devices can be recognized on boot. You can even use WIFI dongles as from Attitude Adjustment 12.09-RC1 it works just fine. USB Dongle tested and working: Edimax EW-7722UnD a/b/g/n - Tested in 40mhz HT mode. Max speed measured (TCP): 20mbit (dirty conditions). Over USB hub you could add few more which makes this even a very good base station.

On USB port - solder first pin from top.

More info can be found on: http://linux.jezgra.net/2013/02/sx763-hack/

Please note that side-effects of this power mod are unknown. (Probably there should be no 'ugly-usb-patch' added anymore, so it doesn't give power on already powered pin.)

There are 10 gpio pins that i was able to find. Marked them on picture.

There is a tarball with basic code at http://opensource.sagemcom.com/index.php?id=54

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