Update: uMon is now booting from SD

Jarielle Catbagan jcatbagan93 at gmail.com
Tue Jul 7 17:23:49 UTC 2015

On Jul 7, 2015 4:49 AM, "Ed Sutter" <ed.sutter at alcatel-lucent.com> wrote:
> Jarielle,
> Great!
> Two (last) minor suggestions...
> 1. Mention the script in the documentation file.
> 2. In the script you may as well include the final step that you have in
the documentation
> for copying the MLO file to the card...
>    cd ~
>    mkdir mnt
>    ...
>    rmdir mnt
> Other than that, it looks good to me.
> Good hunting regarding the cluster error issue!
> Ed

Thanks.  Doc and script are now updated to reflect the minor suggestions.
I added a part in the "FAT Mode" section to refer to the script and I added
the last remaining steps in the doc to the script.  The links to the files
are the same as before.

How are the doc and script so far?

Just for completeness, I'm going to get the raw mode image built as well
with the Configuration Header and GP Header prepended.  I'm thinking of
also updating the script even further to allow the user to select whether
they would want to format the SD card for "raw" or FAT mode.

I'll then send another draft of the files for your review.

>> Ed,
>> Thank you for your suggestions.  I have taken them into account when
>> improving the document.
>> Here is the second draft of the doc:
>> https://github.com/jrcatbagan/umon/blob/dev/ports/beagleboneblack/README
>> .
>> I have also created a script that automates the process of setting up
>> the SD card.  It can be found here:
>> .
>> I also looked into the error regarding the situation where there is
>> not enough clusters and it turns out that the minimum size for the
>> FAT32 primary partition is around 32MB.  FAT16 on the other hand has a
>> minimum size of around 3MB.  I was using this document as reference:
>> https://staff.washington.edu/dittrich/misc/fatgen103.pdf .   So I went
>> ahead and had the script create the primary partition as FAT16.  I was
>> able to boot uMon from an SD card that was setup with this script.
>> Please let me know what you think about the doc and script so far.
>> Thanks.
>> On Mon, Jul 6, 2015 at 5:10 PM, Ed Sutter <edsutterjr at gmail.com> wrote:
>>> Jarielle,
>>> Excellent!
>>> Couple of  comments...
>>> 1. Since you've got so much detail in there, you may want to include the
>>> names of
>>> the TRM chapter and sections that you reference.  I say this because a
>>> revision may insert
>>> a chapter or a section and that will make the chapter/section numbers
>>> have confusing.
>>> 2. For raw mode description, in the 'dd' line, change "of=/dev/sdc" to
>>> "of=<device>" (where <device> is the sd card).
>>> 3. For fat mode description, you may want to add a "dd if=/dev/zero
>>> of=<device> bs=1M count=1" as the first step just to
>>>       make sure there is no partition table at the base of the SD
card.  If
>>> there is, then the first 'n' in your instructions
>>>       may not do what you want.  I know you mention that the card is
>>> to not be formatted.  This just
>>>       makes sure of that.  So, I walked through your steps, using this
>>> automate:
>>> export SDDEV=/dev/sdc  # User should verify this device.
>>> sudo dd if=/dev/zero of=${SDDEV} bs=128K count=1
>>> echo "n\np\n1\n\n+1M\nt\nc\na\n1\np\nw\n" | fdisk ${SDDEV}
>>>       But when I did the mkfs line in your text, it returned an error:
>>> enough clusters for a 32bit FAT.
>>>       So, I just did "mkfs.vfat /dev/sdc1" and that worked fine.
Honestly, I
>>> don't know the details here,
>>>       so if you can investigate this, that would be great.  Suggest
>>> something like the script above as
>>>       a shortcut.
>>> 4. For UART boot mode, mention that the uMon image that is transferred
>>> boot.bin, not the MLO.
>>> Some other stuff you could add:
>>> - To know for sure what device is your uSD card in your linux box, run
>>> /proc/partitions" before and after
>>> inserting the card and note the difference.
>>> Good stuff,
>>> Ed
>>> Ed,
>>> I finished the first draft of the document.  It can be found here:
>>> . Please feel free to give me any suggestions on how I can improve it
>>> or if I am missing something.  Once you give the green light, I'll
>>> send it to umon-devel as a patch.
>>> Thanks.
>>> On Mon, Jul 6, 2015 at 5:21 AM, Ed Sutter <ed.sutter at alcatel-lucent.com>
>>> wrote:
>>> On 7/5/2015 6:46 PM, Chris Johns wrote:
>>> On 5/07/2015 4:19 am, Ed Sutter wrote:
>>> Ok, I managed to get it to boot using only Linux for formatting the
>>> It wasn't working for me until I just read your email and realized I did
>>> not mark
>>> the partition active.  After doing that it booted!
>>> So here are the steps I walked through
>>> (extracted from: http://forum.xda-developers.com/showthread.php?t=502095
>>> :
>>> 1. Verify the partition that the SD card installs as:
>>>        - cat /proc/paritions (without the uSD)
>>>        - Insert uSD card
>>>        - cat /proc/paritions (note the difference)
>>> Using /dev/sdc as our partition:
>>> 2. sudo fdisk /dev/sdc
>>>       - delete all paritions with 'd' command (d1/d2/d3/d4) as needed
>>>       - use 'n' command to create partition 1
>>>       - use 't' command to relabel partition 1 to 'c'
>>>       - use 'a' command to make the parition active
>>>       - use 'p' to show something like:
>>>      Device Boot      Start         End      Blocks   Id  System
>>> /dev/sdc1   *        2048     3932159     1965056    c  W95 FAT32 (LBA)
>>>        - use 'w' to write to the card
>>> 3. Run sudo mkfs.vfat /dev/sdc1
>>> 4. Mount /dev/sdc1 as /media/boot (or whatever)
>>> 5. Copy MLO to /media/boot
>>> 6. Run sync; unmount /media/boot
>>> 7. Put card in BBB, reset with boot button depressed.
>>> A simple request to place in the doco early is to create a root
>>> partition only as large as you need and not use whole disk size in the
>>> root partition. Users should be encouraged to add other partitions they
>>> can mount as read/write to store a kernel and/or user data.
>>> Chris
>>> _______________________________________________
>>> Yep, for sure... my example above was lame...
>>> Functionally ok, but not considering the fact that the SD card will have
>>> other "stuff".  Also, Chris, IIRC, you mentioned that FAT-booting may
not be
>>> the right way to go ultimately.  So, for now at least, it will be good
>>> cover
>>> both modes of booting until we get a better grip on which approach to
>>> take.
>>> Jarielle, I can add detail on raw mode to whatever you initially write
>>> if you want me to...
>>> Ed
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