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Windows CE 5.0 - MAC-address change - reset after reboot RRS feed

  • Question

  • I have a car diagnostics device which is running windows CE 5. 

    I am trying to change mac-address in HKEY_LOCAL_MACHINE\Comm\DM9CE1\Parms\MACAddress in without success. I am using CEregeditor to gain access and change the mac-add.  Once i click save it shows it as changed on the reg editor but when i reboot the device that changes are lost.

    No changes are stored and its as though the firmare is restricted.  i have tried to flash the firmware with factory NK.bin file which completes successfully however, the old boot custom welcome screen is still there leading me to believe that the flash failed.

    Any pointer would be a great help.  Its like the device looks at another location when booting up but not sure where. Complete NOOb wen it comes to win CE.

    Thursday, October 3, 2019 1:28 PM

All replies

  • Registry persistence is not on by default because it is custom for every device.  Since you are a NOOb, you should probably work with your OEM, or accept the MAC the way it is.  Note that even if you change it in the registry, that may not actually change the MAC - again that is device specific.

    On the other hand, what is CERegeditor?  My registry editor flushes the registry, but other do not.  No flush, no persistence.


    Bruce Eitman
    Senior Enginer
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    Thursday, October 3, 2019 3:48 PM
    Moderator
  • And the bootlogo is probably stored in flash somewhere, read by the bootloader and shown on the display. It has nothing to do with the kernel (NK.bin) itself.

    Good luck,

    Michel Verhagen, eMVP
    Check out my blog: https://guruce.com/blog

    GuruCE
    Microsoft Embedded Partner
    NXP Proven Partner
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    Thursday, October 3, 2019 6:08 PM
    Moderator
  • Hi, thanks for taking time to answer.

    This has been done on other devices before but for some reason on this one it is not. The OEM has gone in to liquidation and I have no support from them. My SD card is corrupt and the only way to make my unit work again is to change the mac-address via registry which will then match the new software mac-address.  At the moment I am getting wifi mac-address mismatch within the device OS environment.

    So, i take it you can enable or disable registry persistence by altering a registry key? where do i find this?

    CERegistry editor is a free program for editing the registry of CE devices.  I have also used remote tools registry editor which comes with visual studio 2008 to no avail.  It allows me to change it but as soon as I restart the changes are lost. a person from another forum has suggested i create a registry key and save it to the flash memory of the device then access the file via explorer and run the file to see if the changes are persisted. Thoughts?  

    Sunday, October 6, 2019 11:19 PM
  • How do i access the files on the flash? it seems as though a file is instructing the bootloader to load factory defaults each time it loads wiping any changes?
    Sunday, October 6, 2019 11:20 PM
  • So, i take it you can enable or disable registry persistence by altering a registry key? where do i find this?

    No, you got that wrong. Registry persistence is an option an OEM enables or disables when configuring the OS design (kernel configuration) in Platform Builder. It cannot be enabled or disabled later at runtime.

    The only way forward would be to create a program that changes the MAC address in the registry and then rebinds the adapter.

    More info here: https://groups.google.com/forum/#!msg/microsoft.public.windowsce.embedded/oy4MjhHZt3I/ljbuGzMt0vQJ


    Good luck,

    Michel Verhagen, eMVP
    Check out my blog: https://guruce.com/blog

    GuruCE
    Microsoft Embedded Partner
    NXP Proven Partner
    https://guruce.com
    Consultancy, training and development services.

    Interested in WEC on i.MX6?
    Get the only 100% stable and best performing i.MX6 BSP for WEC7 and WEC2013 here: https://guruce.com/imx6

    Sunday, October 6, 2019 11:25 PM
    Moderator
  • All of your questions are very device specific. We know nothing about the actual device, and we cannot know anything about it. The OEM really is the only one, and since they're out of business, all you can do is hack.

    If you have a JTAGger you could possibly find out exactly what is happening. Question is; is it worth it?

    You can spend months on this...


    Good luck,

    Michel Verhagen, eMVP
    Check out my blog: https://guruce.com/blog

    GuruCE
    Microsoft Embedded Partner
    NXP Proven Partner
    https://guruce.com
    Consultancy, training and development services.

    Interested in WEC on i.MX6?
    Get the only 100% stable and best performing i.MX6 BSP for WEC7 and WEC2013 here: https://guruce.com/imx6

    Sunday, October 6, 2019 11:28 PM
    Moderator