Kernel reads Ethernet MAC address from NVRAM (and nowhere else) if

  MACFROMNVRAM is set. This is set in HdrSrc for Customer F machines.

Detail:
  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
  checksums).

  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.

Admin:
  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'

VersionASM

@@ -6,9 +6,9 @@
                         GBLS    Module_MinorVersion
                         GBLS    Module_Date
                         GBLS    Module_FullVersion
-Module_MajorVersion     SETS    "5.08"
-Module_Version          SETA    508
+Module_MajorVersion     SETS    "5.09"
+Module_Version          SETA    509
 Module_MinorVersion     SETS    ""
-Module_Date             SETS    "01 Dec 1999"
-Module_FullVersion      SETS    "5.08"
+Module_Date             SETS    "20 Jan 2000"
+Module_FullVersion      SETS    "5.09"
                         END

VersionNum

-/* (5.08)
+/* (5.09)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
  *
  */
-#define Module_MajorVersion_CMHG        5.08
+#define Module_MajorVersion_CMHG        5.09
 #define Module_MinorVersion_CMHG        
-#define Module_Date_CMHG                01 Dec 1999
+#define Module_Date_CMHG                20 Jan 2000
 
-#define Module_MajorVersion             "5.08"
-#define Module_Version                  508
+#define Module_MajorVersion             "5.09"
+#define Module_Version                  509
 #define Module_MinorVersion             ""
-#define Module_Date                     "01 Dec 1999"
+#define Module_Date                     "20 Jan 2000"
 
-#define Module_FullVersion              "5.08"
+#define Module_FullVersion              "5.09"

s/Middle

@@ -1283,6 +1283,7 @@ IOST_BATMAN     * 64    ;Stork keyboard/battery controller seems to be present
 ;                 by this call in preference to a locally provided value.
 
 40
+ [ :LNOT: MACFROMNVRAM
         MOV     r0, #0
         LDRB    r1, [ r0, #RawMachineID ]               ; The family byte
         TEQ     r1, #&81                                ; Is this a custom part?
@@ -1312,9 +1313,10 @@ IOST_BATMAN     * 64    ;Stork keyboard/battery controller seems to be present
         ]
         MOV     r1, #0                                  ; Top 16 bits are zero
         ExitSWIHandler
+ ]
 
 ExitNoEthernetAddress
-        [ :LNOT: STB
+        [ :LNOT: STB :LAND: :LNOT: MACFROMNVRAM
         MOV     r0, #0
         MOV     r1, #0
         ExitSWIHandler
@@ -1329,7 +1331,7 @@ ExitNoEthernetAddress
         ExitSWIHandler
         ]
 
-        [ STB
+        [ STB :LOR: MACFROMNVRAM
 GetMachineAddressCMOS
 ; Out:  r0 = lower 4 bytes (or 0)
 ;       r1 = upper 2 bytes (or 0)