# MAC Address / NVRAM Lost issue

**URL:** <https://forums.digi.com/t/mac-address-nvram-lost-issue/3739>\
**Category:** NET+OS\
**Tags:** nvram, mac-address\
**Created:** [October 15, 2007, 2:38pm UTC](https://forums.digi.com/t/mac-address-nvram-lost-issue/3739 "2007-10-15T14:38:52Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ezimmerman](https://avatars.discourse-cdn.com/v4/letter/e/e56c9b/32.png) [@ezimmerman](https://forums.digi.com/u/ezimmerman)\
**Post date:** [October 15, 2007, 2:38pm UTC](https://forums.digi.com/t/mac-address-nvram-lost-issue/3739/1 "2007-10-15T14:38:52Z")

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1. If you add items to the end of structure devBoardParamsType should the NVRAM settings be invalidated? I am losing my MAC address after updating the image.bin.

2. If I should not be changing devBoardParamsType at all, what can I use to save misc NVRAM settings?

3. If I should be able to append items to that struct, what am I doing wrong that things are getting invalidated/reset?

Thanks,  
Eric

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<div class="post-metadata">

**Author:** ![ezimmerman](https://avatars.discourse-cdn.com/v4/letter/e/e56c9b/32.png) [@ezimmerman](https://forums.digi.com/u/ezimmerman)\
**Post date:** [October 15, 2007, 4:34pm UTC](https://forums.digi.com/t/mac-address-nvram-lost-issue/3739/2 "2007-10-15T16:34:56Z")

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It seems like it is lost any time I make a change to devBoardParamsType…

Does anyone know how I can save some items to NVRAM without causing the MAC Address to be lost?

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<div class="post-metadata">

**Author:** ![ezimmerman](https://avatars.discourse-cdn.com/v4/letter/e/e56c9b/32.png) [@ezimmerman](https://forums.digi.com/u/ezimmerman)\
**Post date:** [October 16, 2007, 12:50pm UTC](https://forums.digi.com/t/mac-address-nvram-lost-issue/3739/3 "2007-10-16T12:50:23Z")

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I figured out a way, but I’m still interested in those who have modified devBoardParamsType. There is a size in the structure meant for detecting an increased number of settings, but it is not used. I am wondering if anyone has implemented this…

fyi: I froze the devBoardParamsType structure, created a new structure and wrote it directly after the devBoardParams in NVRAM. I used an ID to detect whether this was the first time written to and to initialize certain parameters accordingly. Worked nice.