[Dnsmasq-discuss] [PATCH] Delay DHCP replies for Raspberry Pi clients

Floris Bos bos at je-eigen-domein.nl
Wed Mar 29 16:24:45 BST 2017


On 03/29/2017 05:02 PM, Albert ARIBAUD wrote:
> Le Wed, 29 Mar 2017 14:48:48 +0200
> Floris Bos <bos at je-eigen-domein.nl> a écrit:
>> The PXE boot firmware implementation of the Raspberry Pi 3
>> has a bug causing it to fail if it receives replies
>> instantly.
>> As a workaround ensure there is a minimum delay of one
>> second if the client is a Pi.
>> On Linux it looks up the exact receive time of the UDP
>> packet with the SIOCGSTAMP ioctl to prevent multiple
>> delays if multiple packets come in around the same time,
>> or if there already was a delay caused by a ping check.
> Just a side question: can't / won't the boot firmware be fixed?

There is a fix.
However that requires sticking a SD card with the newer boot firmware in 
the Pi, and leaving it in permanently.

To be able to PXE boot without SD card, the firmware in the ROM of the 
SoC has to be used, which is not reflashable, and -at least for the 
devices currently out there- comes with this bug.

Yours sincerely,

Floris Bos

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