Factory Reset + .CFG Restore = Massive NVRAM changes normal?

[cvx01]

Hello All,

If you restore a .cfg file (NVRAM Backup from GUI) on the N66U, shouldn't it restore ALL NVRAM settings, except those that are volatile in nature?

Here is why I ask...

I recently exported NVRAM (nvram show)
Performed a settings backup via GUI (.CFG file through GUI)
Factory Reset
NVRAM Reset
Restored original .CFG file via GUI
Exported NVRAM again (nvram show)
Then compared (diffed) the before and after nvram dumps

I noticed a boatload of NVRAM changes, deletions, and additions

Theoretically, the only changes I should have seen would have been volatile/dynamic fields, like time stamps or non-reserved DHCP assignments.

The changes do not appear to be small changes either. Below is an example of fields deleted after the nvram was compared before and after. This appears to be low level radio settings and not your usual stuff.

Example of Fields Deleted:
pci/2/1/measpower1=0x7f
pci/2/1/measpower2=0x7f
pci/2/1/measpower=0x7f
pci/2/1/noiselvl2ga0=31
pci/2/1/noiselvl2ga1=31
pci/2/1/noiselvl2ga2=31
pci/2/1/noiselvl5gha0=31
pci/2/1/noiselvl5gha1=31
pci/2/1/noiselvl5gha2=31
pci/2/1/noiselvl5gla0=31
pci/2/1/noiselvl5gla1=31
pci/2/1/noiselvl5gla2=31
pci/2/1/noiselvl5gma0=31
pci/2/1/noiselvl5gma1=31
pci/2/1/noiselvl5gma2=31
pci/2/1/noiselvl5gua0=31
pci/2/1/noiselvl5gua1=31
pci/2/1/noiselvl5gua2=31
pci/2/1/ofdmlrbw202gpo=0
pci/2/1/pa2ga0=0xfe72,0x14c0,0xfac7
pci/2/1/pa2ga1=0xfe80,0x1472,0xfabc
pci/2/1/pa2ga2=0xfe82,0x14bf,0xfad9

The moral of the story seems to be, factory resetting and restoring perhaps may resolve issues, even if you restore your old settings file. Previously, I'm sure some of us were under the impression this method would restore the problem. From what I see above, some fields either are ignored on the restore or omitted from the .CFG backup.

Can anyone shed light on this?

Thanks

 

[RMerlin]

I don't know, but in any case it certainly does not mean that you can safely reset to factory default and reload your old saved backup. An invalid setting present in your backup will STILL get reapplied if you reload a saved backup that contain that setting. And a new default value generated by the firmware can still be overwritten by your backup.