catenaccio escribió:Una duda. Los que teníamos la consola comprada con firmware 3.x y hemos ido actualizando con el paso de tiempo hasta 4.x... si hacemos un reset de fábrica recuperamos de nuevo la 3.x???
Para nada, es más cada vez que actualizas "matas" un fusible
Anti-downgrade
The first bootloader verifies FUSE_RESERVED_ODM7 to prevent downgrading. How many fuses are expected to be burnt depends the device's unit type as below.
If too many fuses are burnt the bootloader will panic immediately.
If too few are burnt, the bootloader will enable fuse programming and write the expected value to fuse indexes 0x3A and 0x3C. Afterwards, fuse programming is disabled and the panic value 0x21 is written to PMC_SCRATCH200 register (0x7000EC40). Finally, the watchdog timer is initialized and programmed to force a reset.
On a subsequent boot, after the anti-downgrade fuses are checked again, the PMC_RST_STATUS register (0x7000E5B4) is checked and if set to 0x01 (watchdog reset) the PMC_SCRATCH200 register (0x7000EC40) will be checked for the panic value 0x21. PMC_RST_STATUS will only be set back to 0 (power on reset) if the fuse count matches the new expected value, otherwise the system will panic.