jwitch
Posts: 1
Joined: Tue May 24, 2016 12:13 pm

PXE OTP/GPIO testing

Fri Jul 01, 2016 10:44 am

I understand that USB/PXE boot is still being tested. Apparently these features are enabled by writing an OTP bit and pulling a GPIO pin.

Therefore, presumably we will need an SD card with a boot.txt config something along the lines of "program_enable_pxe=1" to initially enable PXE booting? Could someone enlighten me what that config is and which GPIO to pull so that I can see DHCP/PXE packets with wireshark?

Many thanks

fruitoftheloom
Posts: 20903
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: PXE OTP/GPIO testing

Fri Jul 01, 2016 11:10 am

jwitch wrote:I understand that USB/PXE boot is still being tested. Apparently these features are enabled by writing an OTP bit and pulling a GPIO pin.

Therefore, presumably we will need an SD card with a boot.txt config something along the lines of "program_enable_pxe=1" to initially enable PXE booting? Could someone enlighten me what that config is and which GPIO to pull so that I can see DHCP/PXE packets with wireshark?

Many thanks
Please be aware that is is only for the RPi 3B at present and has already been discussed:

viewtopic.php?f=63&t=138071

viewtopic.php?f=91&t=138786&start=50

search.php?keywords=pxe&t=137932&sf=msgonly

etcetera etcetera etcetera
Retired disgracefully.....

gregeric
Posts: 1509
Joined: Mon Nov 28, 2011 10:08 am

Re: PXE OTP/GPIO testing

Fri Jul 01, 2016 11:17 am

Hi jwitch & welcome to the forums :roll:

See https://github.com/raspberrypi/document ... /Readme.md

fruitoftheloom
Posts: 20903
Joined: Tue Mar 25, 2014 12:40 pm
Location: Delightful Dorset

Re: PXE OTP/GPIO testing

Fri Jul 01, 2016 11:29 am

gregeric wrote:Hi jwitch & welcome to the forums :roll:

See https://github.com/raspberrypi/document ... /Readme.md


This is preliminary information used by the beta testers for the development of the bootcode for mass storage and ethernet boot, but it is currently incorrect and not working.
Retired disgracefully.....

User avatar
0xFF
Posts: 202
Joined: Tue Nov 20, 2012 7:52 pm
Location: Poland

Re: PXE OTP/GPIO testing

Fri Jul 15, 2016 12:31 pm

Is

Code: Select all

program_usb_boot_mode=1
option reversible ?

Can I disable usb boot option back, with?

Code: Select all

program_usb_boot_mode=0
AFAIK OTP means one-time programming read-only memory ;-)

Aydan
Posts: 699
Joined: Fri Apr 13, 2012 11:48 am
Location: Germany, near Lake Constance

Re: PXE OTP/GPIO testing

Fri Jul 15, 2016 2:53 pm

0xFF wrote:Is

Code: Select all

program_usb_boot_mode=1
option reversible ?

Can I disable usb boot option back, with?

Code: Select all

program_usb_boot_mode=0
AFAIK OTP means one-time programming read-only memory ;-)
AFAIK it's not reversible, but why would you need to. USB boot is the last boot option, so as long as an SD card is inserted with valid boot files, you won't even get to USB.

Regards
Aydan

Return to “Advanced users”