cairnarvon
Posts: 18
Joined: Fri Aug 10, 2012 7:25 pm

booting a pi without an SD card

Wed Jun 26, 2013 6:02 pm

What would you see on the screen if you did this? For example with no SD card or a blank SD card?

User avatar
raspberrypiguy1
Posts: 379
Joined: Sun Sep 02, 2012 7:01 pm

Re: booting a pi wihtout an SD card

Wed Jun 26, 2013 6:05 pm

You would see absolutely nothing at all... Just a blank screen

The Raspberry Pi Guy
Matt, The Raspberry Pi Guy YouTube channel, author of Learn Robotics with Raspberry Pi, available now: http://mybook.to/raspirobots, Computer Science & Electronics Undergraduate at The University of Edinburgh

User avatar
duberry
Posts: 379
Joined: Mon Jan 28, 2013 10:44 pm
Location: standing on a planet that's evolving. And revolving at nine hundred miles an hour

Re: booting a pi wihtout an SD card

Wed Jun 26, 2013 6:08 pm

iv heard

with model A in some case you can boot from usb

with model b you need sdcard( fat boot partition ) to boot
lend me your arms, fast as thunderbolts, for a pillow on my journey.
If the environment was a bank, would it be too big to fail
so long; and thanks for all the pi

User avatar
CopterRichie
Posts: 131
Joined: Tue Mar 26, 2013 3:14 am
Location: Los Angeles CA.

Re: booting a pi wihtout an SD card

Wed Jun 26, 2013 6:25 pm

Sure would have been nice to have network booting. Maybe Rev. C.

jawbonegroove
Posts: 37
Joined: Sun Jun 23, 2013 8:17 am
Location: pdx/usa
Contact: Website

Re: booting a pi wihtout an SD card

Wed Jun 26, 2013 7:45 pm

sd boot + netboot + usb boot + nand boot partition + serial terminal +config.txt boot_priority=1

(1 == "yespleasek?")

User avatar
alexeames
Forum Moderator
Forum Moderator
Posts: 2869
Joined: Sat Mar 03, 2012 11:57 am
Location: UK
Contact: Website

Re: booting a pi wihtout an SD card

Wed Jun 26, 2013 9:14 pm

CopterRichie wrote:Sure would have been nice to have network booting. Maybe Rev. C.
If you take the SD card out, you'll have notwork booting. Will that do? :lol:
Alex Eames RasPi.TV, RasP.iO

jawbonegroove
Posts: 37
Joined: Sun Jun 23, 2013 8:17 am
Location: pdx/usa
Contact: Website

Re: booting a pi wihtout an SD card

Wed Jun 26, 2013 9:18 pm

it'd be nice, for all the practicality of remote pi access, to be able to determine boot through software. see my last.

User avatar
redhawk
Posts: 3465
Joined: Sun Mar 04, 2012 2:13 pm
Location: ::1

Re: booting a pi wihtout an SD card

Wed Jun 26, 2013 9:40 pm

Even if you could boot from USB there wouldn't be much point when you need the USB port for keyboard, mouse, wifi or even LAN functionality.

Richard S.

jawbonegroove
Posts: 37
Joined: Sun Jun 23, 2013 8:17 am
Location: pdx/usa
Contact: Website

Re: booting a pi wihtout an SD card

Wed Jun 26, 2013 10:18 pm

right now i'm running arch xfce headless over vnc ... from basically anywhere in the world. if i was abroad, i might like the option of booting from two or three sources. or keep a failsafe image on a usb stick for a server i only physically see once a month. or stick a recovery shell in a nand boot.

User avatar
mahjongg
Forum Moderator
Forum Moderator
Posts: 12354
Joined: Sun Mar 11, 2012 12:19 am
Location: South Holland, The Netherlands

Re: booting a pi wihtout an SD card

Wed Jun 26, 2013 10:51 pm

There is no BIOS ROM in the PI, just a very small bit of boot code for the GPU.

the boot code in the PI's GPU is very simple, and cannot handle a USB memory device behind a hub. Thats why its theoretically possible on a model A to boot from USB, but not on the model B which has a hub built in.
AFAIK, although is is claimed to be possible in theory, I have never read about anybody who actually demonstrated booting via USB! :|

Also, as the PI has only a single USB port, so you can either boot the PI through USB, OR use the USB port for something else, but not both! As the moment you try to add a hub to the equation, USB booting stops being possible!

So in any practical sense USB booting isn't a sensible option.

Bit this limitation isn't a big deal, as the PI can simply do only the first boot stage from the SD-card, but then switch over to something else for the rest of the boot process! Thats should be enough for all normal applications. You could use a (micro) SD-card soldered to the board, for that first stage, but still do the real booting from a thumb drive (or whatever else you fancy).

Joe Schmoe
Posts: 4277
Joined: Sun Jan 15, 2012 1:11 pm

Re: booting a pi wihtout an SD card

Thu Jun 27, 2013 12:50 am

AFAIK, although is is claimed to be possible in theory, I have never read about anybody who actually demonstrated booting via USB!

Also, as the PI has only a single USB port, so you can either boot the PI through USB, OR use the USB port for something else, but not both! As the moment you try to add a hub to the equation, USB booting stops being possible!

So in any practical sense USB booting isn't a sensible option.
1) I'm 98% sure that at least one of dom or one of the other "top dogs" here has done it - and reported so on this board. There was a discussion of it a few months ago, and they said that it had been done (by them).

2) It occurs to me that the only way(s) you'd be able to tell that it worked (that it had, in fact, booted) would be:
a) You would see stuff on the HDMI (or composite) screen. Also audio. But, as noted, you wouldn't be able to mouse or keyboard anything.
b) You could log in and interact normally via the serial port.
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

User avatar
rpdom
Posts: 15428
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: booting a pi wihtout an SD card

Thu Jun 27, 2013 1:48 am

Joe Schmoe wrote:
AFAIK, although is is claimed to be possible in theory, I have never read about anybody who actually demonstrated booting via USB!

Also, as the PI has only a single USB port, so you can either boot the PI through USB, OR use the USB port for something else, but not both! As the moment you try to add a hub to the equation, USB booting stops being possible!

So in any practical sense USB booting isn't a sensible option.
1) I'm 98% sure that at least one of dom or one of the other "top dogs" here has done it - and reported so on this board. There was a discussion of it a few months ago, and they said that it had been done (by them).
Yes, I remember seeing that one of the RPF have done a USB boot of sorts on a model A. I believe it worked in OTG mode, so had to be connected to a PC running special software. This doesn't really help us though.

TBH I don't really see the problem. You can use a low capacity SD card, even a cut down one so it doesn't protrude - glue it in place if you must, or solder it on wires so you can remove it if it fails, and set the kernel parameters to have a USB or NFS root file system.

User avatar
ChromeBlue
Posts: 19
Joined: Wed Jun 26, 2013 3:26 pm
Location: Hannibal, MO

Re: booting a pi wihtout an SD card

Thu Jun 27, 2013 3:10 am

redhawk wrote:Even if you could boot from USB there wouldn't be much point when you need the USB port for keyboard, mouse, wifi or even LAN functionality.

Richard S.
A hub fixes that problem.
Frito: Yah I know this place pretty good, I went to law school here.

Pvt. Joe Bowers: In Costco?
----------
From Idiocracy - funniest/scariest move ever.

User avatar
rpdom
Posts: 15428
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: booting a pi wihtout an SD card

Thu Jun 27, 2013 4:51 am

ChromeBlue wrote:
redhawk wrote:Even if you could boot from USB there wouldn't be much point when you need the USB port for keyboard, mouse, wifi or even LAN functionality.

Richard S.
A hub fixes that problem.
No. The USB boot on the Pi won't work through a hub. It uses USBOTG, where the Pi is the USB slave device and needs to be conected to a USB host/master device (like a PC).

User avatar
solar3000
Posts: 1051
Joined: Sat May 18, 2013 12:14 am

Re: booting a pi wihtout an SD card

Thu Jun 27, 2013 12:54 pm

I use the default raspbian.
A newly created SD has two partitions, a vfat and a linux.
I haven't tried it yet, but I would guess if I modified the vfat files to go and mount a USB flash drive or a hard drive on a USB hub, it would use the USB flash drive instead of the SD card partition 2.
Then I would guess after boot up I would get:
SD card partition 1 ==> /boot
USB flash/hard drive ==> /
Antikythera

User avatar
rpdom
Posts: 15428
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: booting a pi wihtout an SD card

Thu Jun 27, 2013 1:48 pm

solar3000 wrote:I use the default raspbian.
A newly created SD has two partitions, a vfat and a linux.
I haven't tried it yet, but I would guess if I modified the vfat files to go and mount a USB flash drive or a hard drive on a USB hub, it would use the USB flash drive instead of the SD card partition 2.
Then I would guess after boot up I would get:
SD card partition 1 ==> /boot
USB flash/hard drive ==> /
Yes, this is very common and fairly easy to do. I use a USB hard drive on one Pi.

Also, for a while I had it so that the / filesystem was on a networked share, but my server is slow and the performance wasn't good. It did mean I could access the Pi file system from other computers when it was switched off, which was good :)

User avatar
solar3000
Posts: 1051
Joined: Sat May 18, 2013 12:14 am

Re: booting a pi wihtout an SD card

Thu Jun 27, 2013 6:31 pm

rpdom wrote:
solar3000 wrote:I use the default raspbian.
A newly created SD has two partitions, a vfat and a linux.
I haven't tried it yet, but I would guess if I modified the vfat files to go and mount a USB flash drive or a hard drive on a USB hub, it would use the USB flash drive instead of the SD card partition 2.
Then I would guess after boot up I would get:
SD card partition 1 ==> /boot
USB flash/hard drive ==> /
Yes, this is very common and fairly easy to do. I use a USB hard drive on one Pi.

Also, for a while I had it so that the / filesystem was on a networked share, but my server is slow and the performance wasn't good. It did mean I could access the Pi file system from other computers when it was switched off, which was good :)

Yeah I was thinking of a networked filesystem over wifi but I think that would give me a heart attack because of the random disconnects.
Antikythera

jawbonegroove
Posts: 37
Joined: Sun Jun 23, 2013 8:17 am
Location: pdx/usa
Contact: Website

Re: booting a pi without an SD card

Fri Jun 28, 2013 2:24 am

i suppose you could alternate loop images.

Return to “General discussion”