• Paul Skirrow's avatar
    Kernel reads Ethernet MAC address from NVRAM (and nowhere else) if · 6760ce30
    Paul Skirrow authored
      MACFROMNVRAM is set. This is set in HdrSrc for Customer F machines.
      If MACFROMNVRAM is TRUE then OS_ReadSysInfo 4 will read the Ethernet MAC
      Address from bytes 0-13 of the NVRAM area, instead of trying to read it
      from anywhere else. (14 bytes are ysed to store 2 copies and 2
      This is intended for use with a 24LC128 device (which has no OTP area
      and no clock).
      Note that these are physical addresses within the device. Logical
      addresses &F0-&FF map to physical addresses &00-&0F.
      A SetMac utility is provided in Customer F 5 !Boot.Utils to enable the MAC
      address to be programmed for prototypes and development machines.
      Since it is dangerous to rely on the NVRAM to hold our MAC address when
      it is not protected in any way, we store two copies of it, each with
      their own checksum. At present only the first copy is used, but the
      plan is to check both copies and both checksums.
      This version of the Kernel needs Programmer/HdrSrc v0.68 or later.
      If MACFROMNVRAM is enabled, ensure that the MACADDRESS tag in the
      NVRAM file is set to point at &F0 and that MACADDRESSCHECKSUM
      is set to point at &F6. Both should have options L and P to ensure
      they are protected from NVRAM resets and other writes.
    Version 5.09. Tagged as 'Kernel-5_09'
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