Booting from SD card needs 2 partitions?
#1
Hi

I have a RPI and installed openELEC from an image file, its working, however the SD card HAS to have 2 partitions, if i remove one (leaving 1 partition only) it doesnt boot with unable to mount the second partition.

Is this by design? or do i just have wacky build that has to see 2 partitions?
Many Thanks
Ashley

© Copyright 2016 - www.ashleygriffin.ca
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#2
by design
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#3
The Raspberry Pi looks for a FAT partition at boot time, it contains the GPU firmware as well as your config.txt and your OS's kernel. There's no bootrom/bios/firmware etc. in hardware. No SD card or missing/invalid FAT partition, no boot.

The OS then needs its own partition, ie ext2/3/4 for Linux.
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#4
Thanks for the info... so this is interesting.

I jad a 1Gb SD card (testing),
Partition 1 = 995Mb (FAT)
Partition 2 = 5mb (FAT)

All data is loaded on to partition 1, it boots and loads, so it appears Linux doesn’t need an EXT format as the above config is working and i can read files from the partition fine.

Ned Scott can you explain the need for 2 partitions, and is it correct that it will need to be FAT only (when its local), so i assume it wont read an NTFS USB stick? will it read an EXT format anything?

The reason i ask this is, Windows will read FAT partitions, however will only see the first one on an SD card (removable) this means you see the "boot" partition but the rest of it you cant see in Windows.

Meaning, a 16Gb SD card will have about 15.something GB partition you cant load anything on, however if i change them like the above, then its usable, doesn’t seem like a great idea to make openELEC need to have 2 partitions?



Many Thanks
Ashley

© Copyright 2016 - www.ashleygriffin.ca
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#5
frumpsnake just explained it. There's two partitions because that's what the hardware looks for.
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#6
They probably get away with using fat as the root partition as they use squashfs
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#7
As openELEC needs 2 partitions, what are the 2 used for, i only have data on the first and it runs fine, whats the second one used for?
Many Thanks
Ashley

© Copyright 2016 - www.ashleygriffin.ca
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#8
(2012-11-24, 02:42)SFX Group Wrote: As openELEC needs 2 partitions, what are the 2 used for, i only have data on the first and it runs fine, whats the second one used for?

The FAT partition is required for booting, and includes firmware, kernel and read only squashfs filesystem.
The second partition is for writable data (gui settings, cached thumbnails, and scraped information about your media library).
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#9
(2012-11-24, 13:53)popcornmix Wrote: The FAT partition is required for booting, and includes firmware, kernel and read only squashfs filesystem.
The second partition is for writable data (gui settings, cached thumbnails, and scraped information about your media library).

Thanks for the clarification, i can see this now on the disk, think i'll get a 4Gb card, 1Gb for the system and 3 for the media, have to see what i can find and depends on price.
Many Thanks
Ashley

© Copyright 2016 - www.ashleygriffin.ca
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#10
You can move the "second partition" from the SD card to a USB memory stick by editing the file cmdline.txt located in the FAT partition of the SD card. This way, you won't need a second partition on the SD card.

Code:
boot=/dev/mmcblk0p1 disk=/dev/sda1 ssh quiet

where /dev/sda1 is your USB memory stick, formatted with a single ext4 partition.

OpenELEC only requires 128MB for the FAT partition, so in theory you could boot OpenELEC with an SD card as small as 128MB, and locate all your XBMC data on the USB memory stick (I'd recommend at least a 4GB memory stick).
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.
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#11
Can this USB stick be a FAT format? it works if the SD card is FAT format on both partitions
Many Thanks
Ashley

© Copyright 2016 - www.ashleygriffin.ca
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#12
Not sure, try it and let us know....
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.
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