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DOS bootsector needed for NOOBS install?

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  DOS bootsector needed for NOOBS install? "Markus R. Kessler" <dimke.fax@uni.de> - 2015-11-19 22:12 +0000
    Re: DOS bootsector needed for NOOBS install? Dave Farrance <DaveFarrance@OMiTTHiSyahooANDTHiS.co.uk> - 2015-11-20 09:58 +0000
      Re: DOS bootsector needed for NOOBS install? Dave Farrance <DaveFarrance@OMiTTHiSyahooANDTHiS.co.uk> - 2015-11-20 10:10 +0000
        Re: DOS bootsector needed for NOOBS install? The Natural Philosopher <tnp@invalid.invalid> - 2015-11-20 10:15 +0000
          Re: DOS bootsector needed for NOOBS install? "Markus R. Kessler" <dimke.fax@uni.de> - 2015-11-20 14:04 +0000
    Re: DOS bootsector needed for NOOBS install? "M.O.B. i L." <mobil@orbin.se> - 2015-11-21 00:51 +0100
      Re: DOS bootsector needed for NOOBS install? Dom <domafp@blueyonder.co.uk> - 2015-11-21 05:47 +0000
        Re: DOS bootsector needed for NOOBS install? "M.O.B. i L." <mobil@orbin.se> - 2015-11-21 11:39 +0100
          Re: DOS bootsector needed for NOOBS install? Dom <domafp@blueyonder.co.uk> - 2015-11-21 21:15 +0000
            Re: DOS bootsector needed for NOOBS install? Martin Gregorie <martin@address-in-sig.invalid> - 2015-11-21 22:09 +0000
              Re: DOS bootsector needed for NOOBS install? "Markus R. Kessler" <dimke.fax@uni.de> - 2015-11-23 10:14 +0000
              Re: DOS bootsector needed for NOOBS install? Dom <domafp@blueyonder.co.uk> - 2015-11-23 11:08 +0000
                Re: DOS bootsector needed for NOOBS install? "Markus R. Kessler" <dimke.fax@uni.de> - 2015-11-23 11:31 +0000

#9964 — DOS bootsector needed for NOOBS install?

Hi all,

sorry, if this has been asked before. But,

I am now working with some Raspberries for around one year, and now I am 
confused about the following:

I can download NOOBS 1.4.x as a zip ball, and on a Linux machine, it is 
always easy to install the image on a brandnew SD card. These cards are 
always formatted with MS DOS VFAT32, and you just have to mount the 
relevant partition, cd to where it is mounted, and extract the whole 
content of the zip archive to it.

After that you can put the SD card into the Rapsberry, boot from it and 
run the setup procedure.

Not so, if you take a used SD card and format it to again have a VFAT32 
filesystem on it
( I do something like "mkdosfs -F 32 /dev/sdb1" ).

A card which you have formatted this way can be used in any MP3 player or 
camera, but when trying to boot your Raspberry from this card, this 
attempt will always fail.

So, there seems to be something different. I just don't know, what 
exactly is missing when formatting a used card.

Does there have to be an "MS DOS master boot record" written to it?

I know that those cards can be purchased "ready-to-use", but I'd like to 
understand, what's going on here.

Thanks for info,
best regards,

Markus


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#9971

"Markus R. Kessler" <dimke.fax@uni.de> wrote:

>...
>Not so, if you take a used SD card and format it to again have a VFAT32 
>filesystem on it
>( I do something like "mkdosfs -F 32 /dev/sdb1" ).
>
>A card which you have formatted this way can be used in any MP3 player or 
>camera, but when trying to boot your Raspberry from this card, this 
>attempt will always fail.

But what about the partition structure?  You need to set that with
"fdisk" before formatting the partition(s).

An unused card will usually have just one large FAT32 partition, but a
card that has Raspbian configured (say) will have a small FAT32
partition and a large ext4 partition.

To place a Raspbian image on a card, you just "dd" the image to the
whole card, usually /dev/sdb (notice that's not /dev/sdb1) and the
partitions will be part of the image. For NOOBS, you need to
re-partition the card with "fdisk" (google for how to use it) so that it
has a single "W95 FAT32 (LBA)" partition occupying the whole card, then
you format the partition as a vfat filesystem.

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#9972

And regarding your question about an "MS DOS master boot record": No,
it's not needed. The Pi's SOC is smart enough to understand the vfat
filesystem and it looks inside that for the file bootcode.bin, which it
loads and runs. bootcode.bin will be supplied as the initial bootloader
file with any OS intended for the Pi.

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#9973

On 20/11/15 10:10, Dave Farrance wrote:
> And regarding your question about an "MS DOS master boot record": No,
> it's not needed. The Pi's SOC is smart enough to understand the vfat
> filesystem and it looks inside that for the file bootcode.bin, which it
> loads and runs. bootcode.bin will be supplied as the initial bootloader
> file with any OS intended for the Pi.
>
But be aware it has to be VFAT...


-- 
the biggest threat to humanity comes from socialism, which has utterly 
diverted our attention away from what really matters to our existential 
survival, to indulging in navel gazing and faux moral investigations 
into what the world ought to be, whilst we fail utterly to deal with 
what it actually is.

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#9975

Am Fri, 20 Nov 2015 10:15:22 +0000 schrieb The Natural Philosopher:

> On 20/11/15 10:10, Dave Farrance wrote:
>> And regarding your question about an "MS DOS master boot record": No,
>> it's not needed. The Pi's SOC is smart enough to understand the vfat
>> filesystem and it looks inside that for the file bootcode.bin, which it
>> loads and runs. bootcode.bin will be supplied as the initial bootloader
>> file with any OS intended for the Pi.
>>
> But be aware it has to be VFAT...

Hi, thanks for the info -- I was just about to test it with EXT2 :-)

BR,

Markus


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#9983

Den 2015-11-19 kl. 23:12, skrev Markus R. Kessler:
> Hi all,
>
> sorry, if this has been asked before. But,
>
> I am now working with some Raspberries for around one year, and now I am
> confused about the following:
>
> I can download NOOBS 1.4.x as a zip ball, and on a Linux machine, it is
> always easy to install the image on a brandnew SD card. These cards are
> always formatted with MS DOS VFAT32, and you just have to mount the
> relevant partition, cd to where it is mounted, and extract the whole
> content of the zip archive to it.
>
> After that you can put the SD card into the Rapsberry, boot from it and
> run the setup procedure.
>
> Not so, if you take a used SD card and format it to again have a VFAT32
> filesystem on it
> ( I do something like "mkdosfs -F 32 /dev/sdb1" ).
>
> A card which you have formatted this way can be used in any MP3 player or
> camera, but when trying to boot your Raspberry from this card, this
> attempt will always fail.
>
> So, there seems to be something different. I just don't know, what
> exactly is missing when formatting a used card.
>
> Does there have to be an "MS DOS master boot record" written to it?
>
> I know that those cards can be purchased "ready-to-use", but I'd like to
> understand, what's going on here.

It must be a bootable W95 FAT32 (LBA) partition. This is from my guide 
at https://github.com/mobluse/coderdojo-raspbian-sv , but I add some 
questions at the end:

##Install##

First you unpack NOOBS on an SD-card. You can use Windows or Mac OS X 
for this, but below is shown for Raspbian Linux.

Skip to next heading if you have a new, blank SD-card.

Use this to list partitions:

     sudo fdisk -l

Use Parted or FDisk to remove all partitions from the SD-card you want 
to format and create a new, bootable W95 FAT32 (LBA) partition, see
[this 
guide](http://qdosmsq.dunbar-it.co.uk/blog/2013/06/noobs-for-raspberry-pi/)
or check this example:

     $ umount /dev/sda1 # Change sda1 to the device you will use.
     $ sudo fdisk /dev/sda

     Command (m for help): d
     Partition number (1-6): 1

     Command (m for help): d
     Partition number (1-6): 2

     Command (m for help): d
     Selected partition 3

     Command (m for help): d
     No partition is defined yet!

     Command (m for help): p

     Disk /dev/sda: 15.9 GB, 15931539456 bytes
     4 heads, 16 sectors/track, 486192 cylinders, total 31116288 sectors
     Units = sectors of 1 * 512 = 512 bytes
     Sector size (logical/physical): 512 bytes / 512 bytes
     I/O size (minimum/optimal): 512 bytes / 512 bytes
     Disk identifier: 0x000825fe

        Device Boot      Start         End      Blocks   Id  System

     Command (m for help): n
     Partition type:
        p   primary (0 primary, 0 extended, 4 free)
        e   extended
     Select (default p): p
     Partition number (1-4, default 1): 1
     Using default value 1
     First sector (2048-31116287, default 2048):
     Using default value 2048
     Last sector, +sectors or +size{K,M,G} (2048-31116287, default 
31116287):
     Using default value 31116287

     Command (m for help): p

     Disk /dev/sda: 15.9 GB, 15931539456 bytes
     4 heads, 16 sectors/track, 486192 cylinders, total 31116288 sectors
     Units = sectors of 1 * 512 = 512 bytes
     Sector size (logical/physical): 512 bytes / 512 bytes
     I/O size (minimum/optimal): 512 bytes / 512 bytes
     Disk identifier: 0x000825fe

        Device Boot      Start         End      Blocks   Id  System
     /dev/sda1            2048    31116287    15557120   83  Linux

     Command (m for help): t
     Selected partition 1
     Hex code (type L to list codes): l

      0  Empty
      1  FAT12
      2  XENIX root      39  Plan 9          83  Linux
      3  XENIX usr
      4  FAT16 <32M      40  Venix 80286     85  Linux extended
      5  Extended
      6  FAT16
      7  HPFS/NTFS/exFAT
      8  AIX
      9  AIX bootable
      a  OS/2 Boot Manag
      b  W95 FAT32
      c  W95 FAT32 (LBA)
      e  W95 FAT16 (LBA)
      f  W95 Ext'd (LBA)
     Hex code (type L to list codes): c
     Changed system type of partition 1 to c (W95 FAT32 (LBA))

     Command (m for help): p

     Disk /dev/sda: 15.9 GB, 15931539456 bytes
     4 heads, 16 sectors/track, 486192 cylinders, total 31116288 sectors
     Units = sectors of 1 * 512 = 512 bytes
     Sector size (logical/physical): 512 bytes / 512 bytes
     I/O size (minimum/optimal): 512 bytes / 512 bytes
     Disk identifier: 0x000825fe

        Device Boot      Start         End      Blocks   Id  System
     /dev/sda1            2048    31116287    15557120    c  W95 FAT32 (LBA)

     Command (m for help): a
     Partition number (1-4): 1

     Command (m for help): p

     Disk /dev/sda: 15.9 GB, 15931539456 bytes
     4 heads, 16 sectors/track, 486192 cylinders, total 31116288 sectors
     Units = sectors of 1 * 512 = 512 bytes
     Sector size (logical/physical): 512 bytes / 512 bytes
     I/O size (minimum/optimal): 512 bytes / 512 bytes
     Disk identifier: 0x000825fe

        Device Boot      Start         End      Blocks   Id  System
     /dev/sda1   *        2048    31116287    15557120    c  W95 FAT32 (LBA)

     Command (m for help): w
     The partition table has been altered!

     Calling ioctl() to re-read partition table.

     WARNING: If you have created or modified any DOS 6.x
     partitions, please see the fdisk manual page for additional
     information.
     Syncing disks.

End of example.

Format and name the SD-card:

     sudo mkdosfs -n dojopi1 -F 32 -I /dev/sda1
(You may need to do `umount /dev/sda1` before. Change sda1 to your 
partition and the name dojopi1 to what you like.)

###Unpack NOOBS to SD-card###

Remove and insert the USB SD-card reader/writer in order to mount 
automatically. Use this to find out where it is mounted:

     mount | grep -i sda1

Stream [NOOBS](http://www.raspberrypi.org/downloads/) down to the 
SD-card using this for small NOOBS files:

     curl -sL http://downloads.raspberrypi.org/NOOBS_latest | bsdtar 
-xvf- -C /media/pi/dojopi1/
alternatively this for big NOOBS files:

     cd /media/pi/dojopi1/
     curl -Lo NOOBS_latest.torrent 
http://downloads.raspberrypi.org/NOOBS_latest.torrent
     ctorrent -p 51414 NOOBS_latest.torrent # Change 51414 to your 
listen port.
     rm NOOBS_latest.torrent
     unzip NOOBS_v1_4_2.zip
     rm NOOBS_v1_4_2.zip

Note: bsdtar doesn't work with the latest very big NOOBS files. Is there 
an updated bsdtar program? Is there a better alternative to ctorrent 
that can download a torrent without a listen port?

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#9985

On 20/11/15 23:51, M.O.B. i L. wrote:
> Den 2015-11-19 kl. 23:12, skrev Markus R. Kessler:
>>
>> Does there have to be an "MS DOS master boot record" written to it?
>>

> It must be a bootable W95 FAT32 (LBA) partition. This is from my guide
> at https://github.com/mobluse/coderdojo-raspbian-sv , but I add some
> questions at the end:

It just has to be the first FAT32 partition on the card. Partition 
number 1. It doesn't have to be bootable - the Pi ignores that flag. The 
Pi will also boot from FAT12 and FAT16, but they might not have enough 
capacity for NOOBS.

The partition doesn't even have to fill the card, it just needs to be 
big enough for the NOOBS install files with a bit in reserve. It gets 
resized anyway.

Dom

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#9987

Den 2015-11-21 kl. 06:47, skrev Dom:
> On 20/11/15 23:51, M.O.B. i L. wrote:
>> Den 2015-11-19 kl. 23:12, skrev Markus R. Kessler:
>>>
>>> Does there have to be an "MS DOS master boot record" written to it?
>>>
>
>> It must be a bootable W95 FAT32 (LBA) partition. This is from my guide
>> at https://github.com/mobluse/coderdojo-raspbian-sv , but I add some
>> questions at the end:
>
> It just has to be the first FAT32 partition on the card. Partition
> number 1. It doesn't have to be bootable - the Pi ignores that flag. The
> Pi will also boot from FAT12 and FAT16, but they might not have enough
> capacity for NOOBS.
>
> The partition doesn't even have to fill the card, it just needs to be
> big enough for the NOOBS install files with a bit in reserve. It gets
> resized anyway.

"Some people may have problems getting their card to boot in the 
Raspberry Pi when wiped and re-partitioned like this. If you have that 
problem, simply make the new partition bootable using the a command." 
http://qdosmsq.dunbar-it.co.uk/blog/2013/06/noobs-for-raspberry-pi/

I had this problem and it was solved with the 'a' command in fdisk. I 
used 'c W95 FAT32 (LBA)' since these SD-cards had that originally.

How do you automate fdisk? Since I do this guide 
https://github.com/mobluse/coderdojo-raspbian-sv on many cards I would 
like to do it in a Bash-script or from Perl.

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#9995

On 21/11/15 10:39, M.O.B. i L. wrote:
>
> How do you automate fdisk? Since I do this guide
> https://github.com/mobluse/coderdojo-raspbian-sv on many cards I would
> like to do it in a Bash-script or from Perl.

Possibly you could send the key sequences though a pipe into fdisk using 
echo or cat. You could also use sfdisk, which can be fed a complete new 
partition table in that way.

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#9996

On Sat, 21 Nov 2015 21:15:13 +0000, Dom wrote:

> On 21/11/15 10:39, M.O.B. i L. wrote:
>>
>> How do you automate fdisk? Since I do this guide
>> https://github.com/mobluse/coderdojo-raspbian-sv on many cards I would
>> like to do it in a Bash-script or from Perl.
> 
> Possibly you could send the key sequences though a pipe into fdisk using
> echo or cat. You could also use sfdisk, which can be fed a complete new
> partition table in that way.

You could also use a HERE document, which works for any program that 
accepts commands, data, etc through stdin. Here's an example:

#!/bin/bash
cat <<END
line one
line two
END
ls

This bash script first runs cat to list the two lines following itself 
and then lists the current directory. IOW the <<END says that the next 
line and all those following it are read by the program (cat) until a 
line containing the text following << is met.

For what you want, a script like: 

#!/bin/bash
sudo fdisk $1 <<END
d
1
d
2
p
w
q
END

should work  - sudo will prompt for the password and fdisk will read its 
commands and their arguments from the HERE document, thus deleting 
partitions 1 and 2, print a list of the remaining partitions (if any), 
write the modified partition table to the disk (SD card) and quit.

Create the script with an editor and remember to make it executable with 
the command:

chmod u+x scriptname

Then a command like "scriptname /dev/sda" will make fdisk make the 
requested changes to the requested SD card (/dev/sda is the built-in SD 
card reader, /dev/sdb etc would work on SD cards in external SD card 
readers, memory sticks or USB hard drives.


-- 
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |

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#10016

Am Sat, 21 Nov 2015 22:09:02 +0000 schrieb Martin Gregorie:

> On Sat, 21 Nov 2015 21:15:13 +0000, Dom wrote:
> 
>> On 21/11/15 10:39, M.O.B. i L. wrote:
>>>
>>> How do you automate fdisk? Since I do this guide
>>> https://github.com/mobluse/coderdojo-raspbian-sv on many cards I would
>>> like to do it in a Bash-script or from Perl.
>> 
>> Possibly you could send the key sequences though a pipe into fdisk
>> using echo or cat. You could also use sfdisk, which can be fed a
>> complete new partition table in that way.
> 
> You could also use a HERE document, which works for any program that
> accepts commands, data, etc through stdin. Here's an example:
> 
> #!/bin/bash
> cat <<END
> line one
> line two
> END
> ls
> 
> This bash script first runs cat to list the two lines following itself
> and then lists the current directory. IOW the <<END says that the next
> line and all those following it are read by the program (cat) until a
> line containing the text following << is met.
> 
> For what you want, a script like:
> 
> #!/bin/bash
> sudo fdisk $1 <<END
> d
> 1
> d
> 2
> p
> w
> q
> END
> 
> should work  - sudo will prompt for the password and fdisk will read its
> commands and their arguments from the HERE document, thus deleting
> partitions 1 and 2, print a list of the remaining partitions (if any),
> write the modified partition table to the disk (SD card) and quit.
> 
> Create the script with an editor and remember to make it executable with
> the command:
> 
> chmod u+x scriptname
> 
> Then a command like "scriptname /dev/sda" will make fdisk make the
> requested changes to the requested SD card (/dev/sda is the built-in SD
> card reader, /dev/sdb etc would work on SD cards in external SD card
> readers, memory sticks or USB hard drives.

Hi,

this is slightly offtopic here, but worth to mention anyway:

When the ISO is written the first time, afterwards the installation /
setup process will boot from the SD card and then attempt to write the
MBR.

Once, during one of my experiments, I forgot to remove the Write
Protection on the Micro-SD to SD adapter, and, guess what?

The setup process continued, though the plastic switch was on "Lock". The
MBR got written corretly and Raspbian finally ran, no matter if the card
was set to RW or RO (!)

This, finally, means, that even a virus or trojan can write to "write-
protected" SD cards. Maybe this is a hardware issue only concerning this
adapter (I have no second one to test), but since it comes from "Intenso",
I assume that it is OK. That's somehow frustrating...

Best regards,

Markus

-- 
Please reply to group only.
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#10017

On 23/11/15 10:11, Markus R. Kessler wrote:
>
> Hi,
>
> this is slightly offtopic here, but worth to mention anyway:
>
> When the ISO is written the first time, afterwards the installation /
> setup process will boot from the SD card and then attempt to write the
> MBR.
>
> Once, during one of my experiments, I forgot to remove the Write
> Protection on the Micro-SD to SD adapter, and, guess what?
>
> The setup process continued, though the plastic switch was on "Lock". The
> MBR got written corretly and Raspbian finally ran, no matter if the card
> was set to RW or RO (!)
>
> This, finally, means, that even a virus or trojan can write to "write-
> protected" SD cards. Maybe this is a hardware issue only concerning this
> adapter (I have no second one to test), but since it comes from
> "Imation", I assume that it is OK. That's somehow frustrating...

The slider on the adaptor/full sized card isn't connected to anything 
inside. It actuates a switch in the SD card socket, which controls 
write-protect in software only. On the Pi A/B that switch is not 
connected to anything and has no effect. On a micro SD card there is no 
such switch mechanism.

Dom

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#10018

Am Mon, 23 Nov 2015 11:08:11 +0000 schrieb Dom:

> On 23/11/15 10:11, Markus R. Kessler wrote:
>>
>> Hi,
>>
>> this is slightly offtopic here, but worth to mention anyway:
>>
>> When the ISO is written the first time, afterwards the installation /
>> setup process will boot from the SD card and then attempt to write the
>> MBR.
>>
>> Once, during one of my experiments, I forgot to remove the Write
>> Protection on the Micro-SD to SD adapter, and, guess what?
>>
>> The setup process continued, though the plastic switch was on "Lock".
>> The MBR got written corretly and Raspbian finally ran, no matter if the
>> card was set to RW or RO (!)
>>
>> This, finally, means, that even a virus or trojan can write to "write-
>> protected" SD cards. Maybe this is a hardware issue only concerning
>> this adapter (I have no second one to test), but since it comes from
>> "Imation", I assume that it is OK. That's somehow frustrating...
> 
> The slider on the adaptor/full sized card isn't connected to anything
> inside. It actuates a switch in the SD card socket, which controls
> write-protect in software only. On the Pi A/B that switch is not
> connected to anything and has no effect. On a micro SD card there is no
> such switch mechanism.

Hi Dom,

I was wondering, because when putting the same Mico-SD-card as a "write-
protected" (full-size) SD-card into a notebook, it was then mounted as 
"RO", as long as the slider was on "Lock". So, this really seems just 
like a "recommendation" to the OS, to please not write data onto it.

Thanks, this makes things clearer!

Best regards,

Markus

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