tigernero
Posts: 109
Joined: Fri Dec 30, 2016 5:51 pm

Error in your usb boot site guide

Fri Aug 16, 2019 1:24 pm

I wanted to let you know that your guide concerning the setting in opt of the value 302000a,
is valid not only for pi2 v1.2 and pi3b but also for pi3a +, in the guide instead you say that the pi3a +
already has the value set instead I had to program it only once for have boot via usb.

If you can edit voice to write that also for pi3a + it should be set otherwise you could mess up thanks.

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B.Goode
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Joined: Mon Sep 01, 2014 4:03 pm
Location: UK

Re: Error in your usb boot site guide

Fri Aug 16, 2019 1:38 pm

The author/maintainer of the documentation you are referring to may not necessarily be a reader of these forums.


If you mean a page such as https://www.raspberrypi.org/documentati ... des/usb.md then at the foot of the page is a link labelled VIEW/EDIT THIS PAGE ON GITHUB which you could use to raise an Issue about the documentation.



The documentation at https://www.raspberrypi.org/documentati ... des/msd.md says quite explicitly
The Raspberry Pi 3A+ and 3B+ are able to boot from USB without any changes
Is it your contention that this is incorrect?

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davidcoton
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Location: Cambridge, UK

Re: Error in your usb boot site guide

Fri Aug 16, 2019 4:10 pm

IIRC, the Pi3A+ originally had the USB boot bit set, but this had to be changed to allow the use of device mode on the USB port (or some other incompatibility). Possibly the documentation never caught up with the change.
Signature retired

tigernero
Posts: 109
Joined: Fri Dec 30, 2016 5:51 pm

Re: Error in your usb boot site guide

Fri Aug 16, 2019 4:40 pm

exact the page to which I referred was the one taken from the raspberry site documentation, this:

https://www.raspberrypi.org/documentati ... des/msd.md

in which it is written:

"The Raspberry Pi 3A + and 3B + are able to boot from USB without any changes"


this is not true for the pi3a + so I had to set otp number 17 with the command
"echo program_usb_boot_mode=1 | sudo tee -a /boot/config.txt"

while for my pi3b + it was already set.

I also have a pi4 4gb but otp 17 has a value "17: 000008b0" completely different from the previous raspberry before the change to "17: 3020000a" I believe it was 17: 120000a "so if I gave that command on pi4 what would happen?

tigernero
Posts: 109
Joined: Fri Dec 30, 2016 5:51 pm

Re: Error in your usb boot site guide

Fri Aug 16, 2019 4:45 pm

I have however opened a commit on github for the correct modification we will see.

trejan
Posts: 355
Joined: Tue Jul 02, 2019 2:28 pm

Re: Error in your usb boot site guide

Fri Aug 16, 2019 4:49 pm

tigernero wrote:
Fri Aug 16, 2019 4:40 pm
I also have a pi4 4gb but otp 17 has a value "17: 000008b0" completely different from the previous raspberry before the change to "17: 3020000a" I believe it was 17: 120000a "so if I gave that command on pi4 what would happen?
Nothing. The boot mode config will be kept inside the bootcode EEPROM on a RPi 4. USB/network boot hasn't been released yet anyway.

tigernero
Posts: 109
Joined: Fri Dec 30, 2016 5:51 pm

Re: Error in your usb boot site guide

Fri Aug 16, 2019 5:17 pm

But when will the startup usb mode on pi4 be released and bit otp 17 always set or not?

with the command

"echo program_usb_boot_mode=1 | sudo tee -a /boot/config.txt" to have value "17: 3020000a"

trejan
Posts: 355
Joined: Tue Jul 02, 2019 2:28 pm

Re: Error in your usb boot site guide

Fri Aug 16, 2019 5:26 pm

tigernero wrote:
Fri Aug 16, 2019 5:17 pm
But when will the startup usb mode on pi4 be released and bit otp 17 always set or not?

with the command

"echo program_usb_boot_mode=1 | sudo tee -a /boot/config.txt" to have value "17: 3020000a"
I wouldn't expect it to be set since that bit does nothing as the firmware will be reading the configuration out of the boot EEPROM.

k-pi
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Joined: Sun Feb 12, 2017 1:46 pm
Location: Upper Hale, Surrey, UK.

Re: Error in your usb boot site guide

Fri Aug 16, 2019 7:20 pm

My RPi3A+ boots from USB out of the box, some users of the RPi0 used them as devices, which having the boot bit set on the RPi3A+ prevented them from doing.

Maybe they now have to get it set by the end user, which will be a backward step, as I use USB booting on all of my RPi3B/B+/A+ & hopefully soon my RPi4B too.

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rpdom
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Location: Chelmsford, Essex, UK

Re: Error in your usb boot site guide

Fri Aug 16, 2019 7:27 pm

k-pi wrote:
Fri Aug 16, 2019 7:20 pm
My RPi3A+ boots from USB out of the box, some users of the RPi0 used them as devices, which having the boot bit set on the RPi3A+ prevented them from doing.

Maybe they now have to get it set by the end user, which will be a backward step, as I use USB booting on all of my RPi3B/B+/A+ & hopefully soon my RPi4B too.
Let me get this straight. You would prefer that the OTP bit is set by default on the Pi 3A+ so that you can use your USB boot without having to boot once off an SD card, but that would mean that people who wanted to use their Pi 3A+ in device mode couldn't do that ever and you're OK with that? :roll:

andrum99
Posts: 691
Joined: Fri Jul 20, 2012 2:41 pm

Re: Error in your usb boot site guide

Sat Aug 17, 2019 2:22 am

tigernero wrote:
Fri Aug 16, 2019 4:40 pm
exact the page to which I referred was the one taken from the raspberry site documentation, this:

https://www.raspberrypi.org/documentati ... des/msd.md

in which it is written:

"The Raspberry Pi 3A + and 3B + are able to boot from USB without any changes"


this is not true for the pi3a + so I had to set otp number 17 with the command
"echo program_usb_boot_mode=1 | sudo tee -a /boot/config.txt"
Things get a little complicated around USB boot - there are two modes:

USB device mode boot
USB host mode boot

That page talks about USB mass storage boot, which is enabled by USB host mode boot, but unfortunately the option to enable USB host mode boot by programming an OTP bit is called program_usb_boot: that option has no effect on the ability of the Pi to use USB device mode boot.

So the page needs to have the following information added:

1. On the Pi 3A+, setting the OTP bit to enable USB host mode boot will prevent that Pi 3A+ from doing USB device mode boot, due to the fact that all Pi 3A+'s have the OTG_ID pin tied to ground. See https://www.raspberrypi.org/forums/view ... 4#p1392654. All but a few thousand early Pi 3A+'s have the USB host mode boot bit UNSET - yours being one with it UNSET.

2. The page needs to correctly distinguish between USB host boot mode and USB device boot mode, which is does not at present. ("The Raspberry Pi 3A + and 3B + are able to boot from USB without any changes" is meant to refer to HOST mode only).

3. It should also mention that the option to enable USB host mode boot, by setting a bit in the OTP, is misnamed in a potentially misleading way.

4. The correct sentence from 2 above would be "The Raspberry Pi 3A + and 3B + are able to use USB host mode boot without any changes", which as you point out is wrong, since all but a few early Pi 3A+'s have the USB host mode boot bit UNSET. So that should read "The Raspberry 3B+ is able to use USB host mode boot without any changes".

andrum99
Posts: 691
Joined: Fri Jul 20, 2012 2:41 pm

Re: Error in your usb boot site guide

Sat Aug 17, 2019 2:28 am

tigernero wrote:
Fri Aug 16, 2019 4:45 pm
I have however opened a commit on github for the correct modification we will see.
Where? I can't see it. Can you provide a direct link to it?

andrum99
Posts: 691
Joined: Fri Jul 20, 2012 2:41 pm

Re: Error in your usb boot site guide

Sat Aug 17, 2019 4:32 am

Never mind - I've filed #1250 to fix this - see https://github.com/raspberrypi/documentation/pull/1250


andrum99
Posts: 691
Joined: Fri Jul 20, 2012 2:41 pm

Re: Error in your usb boot site guide

Sat Aug 17, 2019 6:40 am

tigernero wrote:
Sat Aug 17, 2019 5:32 am
My GitHub Is

https://github.com/raspberrypi/document ... efa1b47525

Ok your modified thanks
That change has already been integrated into the documentation.

k-pi
Posts: 911
Joined: Sun Feb 12, 2017 1:46 pm
Location: Upper Hale, Surrey, UK.

Re: Error in your usb boot site guide

Sat Aug 17, 2019 9:01 am

rpdom wrote:
Fri Aug 16, 2019 7:27 pm
k-pi wrote:
Fri Aug 16, 2019 7:20 pm
My RPi3A+ boots from USB out of the box, some users of the RPi0 used them as devices, which having the boot bit set on the RPi3A+ prevented them from doing.

Maybe they now have to get it set by the end user, which will be a backward step, as I use USB booting on all of my RPi3B/B+/A+ & hopefully soon my RPi4B too.
Let me get this straight. You would prefer that the OTP bit is set by default on the Pi 3A+ so that you can use your USB boot without having to boot once off an SD card, but that would mean that people who wanted to use their Pi 3A+ in device mode couldn't do that ever and you're OK with that? :roll:
Yes, because that is the way it was produced, if you change it you will just cause confusion. :)

If you want a device mode unit, give it a different name. ;)

In this day & age, computers should boot from external USB media, it's the way of the world. 8-)

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