SID Register Guide

= Security ID = So far, all Allwinner A-series SoC come with a bit of memory called 'SID'. So far, for all chips this is 128 bits of freely? usable memory, with a catch. These 128 bits of memory, are not in RAM or ROM, they are so called e-fuses.

By default, the chip ID or revision is written to these fusions and possibly some form of serial number. While modifying is untested at this moment, it is possible to read the fuses.

A few use cases for the SID are, but not limited to:
 * Generate per-device unique MAC address
 * Store/use as an RSA etc key
 * Write in-house serial numbers

Info
SID Base address: 0x01c23800

For Allwinner A83T and H3 the SID address space starts at 0x01c14000, and the e-fuses are at offset 0x200 - so the address to use for these SoCs is 0x01c14200.

SID_KEY[0-3]
Default value: undefined

Offset: 0x0{0, 4, 8, c}

SID_WRITE_DATA
Default value: 0x00000000

Offset: 0x40

We think this is the data register used when programming the SID efuses.

There is also a EFUSE_VDDQ pin (pin T9 on A10) which is normally tied to GND but which we guess needs to have suitable power to enable efuse programming. Details unknown.

SID_WRITE_CTRL
Default value: 0x00000000

Offset: 0x44

Currently known SID's
md.l 0x01c23800 4