sbh7600
Posts: 9
Joined: Sun Oct 01, 2017 1:51 pm

USB Boot

Mon Aug 26, 2019 10:29 am

Why is it that I cant use usb boot on this model.
Raspberry Pi Model B Plus Rev 1.2

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B.Goode
Posts: 11242
Joined: Mon Sep 01, 2014 4:03 pm
Location: UK

Re: USB Boot

Mon Aug 26, 2019 10:34 am

sbh7600 wrote:
Mon Aug 26, 2019 10:29 am
Why is it that I cant use usb boot on this model.
Raspberry Pi Model B Plus Rev 1.2

Because it hadn't been 'invented' when that model was developed and released so the necessary support isn't implemented in the chips on the board.

But you can boot in the conventional manner from the microSD card and run the Operating System from a root filesystem on usb mass storage.

(And please don't let us get into another bike-shedding thread about what 'usb boot' really means... )

sbh7600
Posts: 9
Joined: Sun Oct 01, 2017 1:51 pm

Re: USB Boot

Mon Aug 26, 2019 10:39 am

Thanks.

You are right. I had usb boot before but I cant remember where I found the guide.

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thagrol
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Re: USB Boot

Mon Aug 26, 2019 11:27 am

There ia an alternative approach that, for me, has worked on every model I've tried it on except the 4B.

Use a smal FAT formatted SD card with just bootcode.bin on it.

Not pure, SD card free USB booting I know. But it does allow an older Pi to boot over USB and PXE. The SD card will never get written to so corruption isn't a problem.
Arguing with strangers on the internet since 1993.

All advice given is based on my experience. it worked for me, it may not work for you.
All GPIO pin numbers are BCM numbers.

ddurdle
Posts: 61
Joined: Sat May 04, 2013 12:20 am

Re: USB Boot

Mon Aug 26, 2019 1:33 pm

I use the alternative approach on all my pi devices. I confirmed this weekend that the same approach works on the pi 4b 4GB. I'm in the more complicated situation because I use BTRFS. So, on the SD card I'm storing a boot partition for the purposes of loading an initramfs that has BTRFS support so that I can then boot the USB BTRFS partition. I don't mind the added complication because it still gets me to the end goal of running the OS off USB.

W. H. Heydt
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Location: Vallejo, CA (US)

Re: USB Boot

Mon Aug 26, 2019 1:56 pm

sbh7600 wrote:
Mon Aug 26, 2019 10:29 am
Why is it that I cant use usb boot on this model.
Raspberry Pi Model B Plus Rev 1.2
You have to set the OTP bit on that version of the Pi in order to do boot from USB. The guide is here: https://www.raspberrypi.org/documentati ... des/msd.md

drgeoff
Posts: 11561
Joined: Wed Jan 25, 2012 6:39 pm

Re: USB Boot

Mon Aug 26, 2019 2:08 pm

W. H. Heydt wrote:
Mon Aug 26, 2019 1:56 pm
sbh7600 wrote:
Mon Aug 26, 2019 10:29 am
Why is it that I cant use usb boot on this model.
Raspberry Pi Model B Plus Rev 1.2
You have to set the OTP bit on that version of the Pi in order to do boot from USB. The guide is here: https://www.raspberrypi.org/documentati ... des/msd.md
USB boot is not possible on a B+. That had the 2835 SoC whose internal boot code does not support USB boot. Setting OTP bit(s) does not alter that fact.
Quis custodiet ipsos custodes?

W. H. Heydt
Posts: 14421
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: USB Boot

Mon Aug 26, 2019 3:18 pm

drgeoff wrote:
Mon Aug 26, 2019 2:08 pm
W. H. Heydt wrote:
Mon Aug 26, 2019 1:56 pm
sbh7600 wrote:
Mon Aug 26, 2019 10:29 am
Why is it that I cant use usb boot on this model.
Raspberry Pi Model B Plus Rev 1.2
You have to set the OTP bit on that version of the Pi in order to do boot from USB. The guide is here: https://www.raspberrypi.org/documentati ... des/msd.md
USB boot is not possible on a B+. That had the 2835 SoC whose internal boot code does not support USB boot. Setting OTP bit(s) does not alter that fact.
Point. I missed the "Plus" in there and read it as Pi2Bv1.2 (just about the only Pi where one needs to specify the board revision).

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thagrol
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Location: Darkest Somerset, UK
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Re: USB Boot

Mon Aug 26, 2019 6:37 pm

drgeoff wrote:
Mon Aug 26, 2019 2:08 pm
USB boot is not possible on a B+. That had the 2835 SoC whose internal boot code does not support USB boot. Setting OTP bit(s) does not alter that fact.
Pure boot from USB without an SD card isn't but you can get pretty damned close. See my post above.

Yes, I've tried it. On a 1B (with mounting holes so not the earliest revision), B+, and a 2B (not sure which revision). Can't remember whether I had to set the OTP or not.

My mian interest in doing so was network/PXE boot. USB came for free withthat.
Arguing with strangers on the internet since 1993.

All advice given is based on my experience. it worked for me, it may not work for you.
All GPIO pin numbers are BCM numbers.

RonR
Posts: 2005
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Location: US

Re: USB Boot

Mon Aug 26, 2019 7:07 pm

sbh7600 wrote:
Mon Aug 26, 2019 10:29 am
Why is it that I cant use usb boot on this model.
Raspberry Pi Model B Plus Rev 1.2

I've run every model of Raspberry Pi (1/2/3/4) from a USB drive for the past 6 years.

Running a single script file is all that's required: Running Raspbian from USB Devices : Made Easy

W. H. Heydt
Posts: 14421
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: USB Boot

Mon Aug 26, 2019 7:49 pm

thagrol wrote:
Mon Aug 26, 2019 6:37 pm
Yes, I've tried it. On a 1B (with mounting holes so not the earliest revision), B+, and a 2B (not sure which revision). Can't remember whether I had to set the OTP or not.
Doesn't work on a Pi2Bv1.1, but it will on a Pi2Bv1.2. The difference being that the Pi2Bv1.2 uses the same SoC as the Pi3B.

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