Post by usbbdm on Jun 20, 2005 13:06:57 GMT -5
When you go diagnostic screen, under "Memory Config", there is "EEPROM Ver.NO." and "00:00". EEPROM has 128 bytes data that holds the configuration of the hardware. So if you clone NVRAM from one box that does not have the same configuration, you might have some problem with TV pictures. When that happens, you might have an incorrect EEPROM data.
When the firmware starts up, it check to see the EEPROM data, (the address is stored at $0022269A, the data is stored at $23ceec), if the computed check sum 32 bit matches the $23cf6c, then these data will be used. Otherwise, on PH 6 and older board, the real EEPROM (24LC01) data will be used. On PH7/8 board, the data is stored on the flash at address $404000.
Now suppose you clone a valid NVRAM from one box (2224/1661) to another box (2244/1161), you have no audio or even image, try to play with the values in the EEPROM area. A single value change in the EEPROM area will let the box use real EEPROM data. If you only want to play with single byte (or bytes) in the EEPROM data, a proper check sum needs to be added. The BDM software soon will provide this feature to let you change the values in the EEPROM area. By this technique, I was able to make 2244/1161 (very old box) work.
When the firmware starts up, it check to see the EEPROM data, (the address is stored at $0022269A, the data is stored at $23ceec), if the computed check sum 32 bit matches the $23cf6c, then these data will be used. Otherwise, on PH 6 and older board, the real EEPROM (24LC01) data will be used. On PH7/8 board, the data is stored on the flash at address $404000.
Now suppose you clone a valid NVRAM from one box (2224/1661) to another box (2244/1161), you have no audio or even image, try to play with the values in the EEPROM area. A single value change in the EEPROM area will let the box use real EEPROM data. If you only want to play with single byte (or bytes) in the EEPROM data, a proper check sum needs to be added. The BDM software soon will provide this feature to let you change the values in the EEPROM area. By this technique, I was able to make 2244/1161 (very old box) work.