[OpenWrt-Devel] Fwd: Re: [PATCH 10/10] brcmfmac: Add support for multiple PCIE devices in nvram.

Rafał Miłecki zajec5 at gmail.com
Mon Apr 20 08:03:27 EDT 2015

On 20 April 2015 at 13:50, Jonas Gorski <jogo at openwrt.org> wrote:
> On Mon, Apr 20, 2015 at 1:29 PM, Rafał Miłecki <zajec5 at gmail.com> wrote:
>> On 20 April 2015 at 11:27, Arend van Spriel <arend at broadcom.com> wrote:
>>>> Following an "nvram erase" none of the needed<key, value>  pairs remain
>>>> in nvram. So we probably can't use nvram in a reliable way to create the
>>>> wireless configuration.
>>> So why do "nvram erase"? The assumption that it is not needed because you
>>> are running an OpenWRT image is wrong or at least only partially true, ie.
>>> for the user-space settings.
>> I agree with Arend. If you're are erasing sensitive wireless info from
>> your device, expect problems. The same will happen if you'll overwrite
>> standard Broadcom PCI device SPROM (which contains the same kind of
>> data).
> At least on older bcm47xx/MIPS devices nvram was also used for (user
> changable) configuration like lan ip address, and consequently erasing
> nvram caused CFE to restore the default values, which should include
> the right wifi configuration values. Several devices even do so when
> holding down reset for a long time at power up*. Does this not happen
> anymore with bcm53xx/ARM? Are user values now stored in a different
> partition?

CFE when restoring NVRAM is using its own minimal copy. It contains
some basic settings needed for SoC to basically work (CPU config, RAM
config, Ethernet MAC). It doesn't contain detailed data like wireless
devices configuration.

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