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PXE OTP/GPIO testing

Posted: Fri Jul 01, 2016 10:44 am
by jwitch
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

Re: PXE OTP/GPIO testing

Posted: Fri Jul 01, 2016 11:10 am
by fruitoftheloom
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

Re: PXE OTP/GPIO testing

Posted: Fri Jul 01, 2016 11:17 am
by gregeric
Hi jwitch & welcome to the forums :roll:

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

Re: PXE OTP/GPIO testing

Posted: Fri Jul 01, 2016 11:29 am
by fruitoftheloom
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.

Re: PXE OTP/GPIO testing

Posted: Fri Jul 15, 2016 12:31 pm
by 0xFF
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 ;-)

Re: PXE OTP/GPIO testing

Posted: Fri Jul 15, 2016 2:53 pm
by Aydan
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