Hi, I have a ADS Tech Instant TV DVB-T USB device that suddenly stopped working when I plugged it in. After that, it was recognized as a "Cypress Semiconductor Corp. CY76803 EZ-USB FX2 USB 2.0 Development Kit" Googling around the internat, I found out that it might be related to a corrupted on-board EEPROM chip. Since I have a second such device, and know some electronics, I first thought I would unsolder open the box, unsolder the EEPROM chips, and the copy the good one on the corrupted one. But such hardware hacking is somewhat dangerous for my devices... Then I realized that the firmware and the driver give me access to the I2C bus, where the EEPROM is connected. So it should be possible to do all this with no hardware hacking. The first step was to hack dibusb-mb.c so that my device was identified as a cold "KWorld/ADSTech Instant DVB-T USB2.0" device, just like it can be done for "Artec T1 USB1.1 TVBOX with AN2235 (faulty USB IDs)". But then I figured out that I still was unsuccessfull when trying to access the EEPROM. With an oscilloscope, I figured out that the I2C bus was running at 400kHz, while the EEPROM chip only supports 100kHz... Fortunately, I could easily hack the dvb-usb-adstech-usb2-02.fw firmware to make the I2C bus run at 100kHz. Thinking about this, the EEPROM chip might be confused by the 400kHz data that it does not understand. I guess my EEPROM might have been corrupted because of this. Then I could read (not that easily, unfortunately) the EEPROM on both the sane device and the damaged device. The sane one starts with: C0 E1 06 33 A3 01 00 The damaged one with: 00 00 00 FF FF FF FF (there are a few other differences, but I'm not sure what they affect, and may rightfully be related to one device being older that the other.) I fixed the first 7 bytes of the damaged EEPROM, copying the first 7 bytes of the sane one. Now, my device works fine again, with an unpatched driver. Out of this experience, I think that you should patch the dvb-usb-adstech-usb2-02.fw firmware that you distribute, as it might break some devices, by corrupting the EEPROM chip. I also guess that "Artec T1 USB1.1 TVBOX with AN2235 (faulty USB IDs)" could be fixed, regrogramming their EEPROM chips, just like I fixed my device (unless they lack an EEPROM chip). I can provide more information to interested people. Cheers, Nicolas _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
