there is a cleaner patch now:

/n/sources/patch/rpi-netboot-dhcpd

On Wed, Jun 3, 2020 at 6:18 PM Skip Tavakkolian <skip.tavakkolian@gmail.com>
wrote:

> The patch is on 9p.io:
>
> /n/sources/patch/dhcpd-rpi-pxeboot
>
>
> On Wed, Jun 3, 2020 at 12:43 PM Skip Tavakkolian <
> skip.tavakkolian@gmail.com> wrote:
>
>> Note that RPi 4 DHCP requests include a parameter request for TFTP Server
>> Name (66).  There is a link in the doc to the diffs for
>> /sys/src/cmd/ip/dhcpd/dhcpd.c. I'll submit a patch to 9p.io soon.
>>
>> On Wed, Jun 3, 2020 at 11:26 AM Skip Tavakkolian <
>> skip.tavakkolian@gmail.com> wrote:
>>
>>>
>>> FYI, I've updated the HOWTO to include RPi4's. It's here:
>>>
>>>
>>> https://docs.google.com/document/d/1hgcsAgk_FJRYW5r7LVeY23sTZN_giUit-8ra-dlW9ng
>>>
>>>
>>>