xz images problem

GoogleGroups
1

Hey,

When I download sdcard images for the BBB, I verify that the sum is correct.
after xzcat, I only find 1 partition in the image, which I cannot mount.

Does this sound familiar.
I cannot believe all images are bad, so it must be something wrong on my computer.
I fail to imagine how xz can be wrong.

Any other ideas?

Kind regards,
Kurt

2

What OS are you using? How are you expanding the xz file?

Greg

3

It's best to use losetup/kpartx to mount it:

$ unxz bone-debian-stretch-iot-armhf-2017-06-04-4gb.img.xz

$ sudo fdisk -l bone-debian-stretch-iot-armhf-2017-06-04-4gb.img
Disk bone-debian-stretch-iot-armhf-2017-06-04-4gb.img: 3.3 GiB,
3565158400 bytes, 6963200 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
Disklabel type: dos
Disk identifier: 0xd12441de

Device Boot Start End
Sectors Size Id Type
bone-debian-stretch-iot-armhf-2017-06-04-4gb.img1 * 8192 6963199
6955008 3.3G 83 Linux

Grab a Loop device:

$ sudo losetup -f
/dev/loop0

$ sudo losetup /dev/loop0 bone-debian-stretch-iot-armhf-2017-06-04-4gb.img

$ sudo kpartx -av /dev/loop0

$ ls /dev/mapper/
control loop0p1

$ mkdir disk
$ sudo mount /dev/mapper/loop0p1 disk/

$ mount | grep disk
/dev/mapper/loop0p1 on
/mnt/data/data/images/bb.org/testing/2017-06-04/stretch-iot/disk type
ext4 (rw,relatime,data=ordered)

$ cd disk/
disk$ ls
bbb-uEnv.txt boot etc ID.txt lost+found mnt opt root
sbin sys usr
bin dev home lib media nfs-uEnv.txt proc run
srv tmp var

Regards,

4

> Hey,
>
> When I download sdcard images for the BBB, I verify that the sum is correct.
> after xzcat, I only find 1 partition in the image, which I cannot mount.
>
> Does this sound familiar.
> I cannot believe all images are bad, so it must be something wrong on my
> computer.
> I fail to imagine how xz can be wrong.

It's best to use losetup/kpartx to mount it:

Well, I used nbd with 'qemu-nbd -c /dev/nbd0 bone....img.
that should work the same.

$ unxz bone-debian-stretch-iot-armhf-2017-06-04-4gb.img.xz

$ sudo fdisk -l bone-debian-stretch-iot-armhf-2017-06-04-4gb.img
Disk bone-debian-stretch-iot-armhf-2017-06-04-4gb.img: 3.3 GiB,
3565158400 bytes, 6963200 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
Disklabel type: dos
Disk identifier: 0xd12441de

Device Boot Start End
Sectors Size Id Type
bone-debian-stretch-iot-armhf-2017-06-04-4gb.img1 * 8192 6963199
6955008 3.3G 83 Linux

Ok, 1 partition. I supposed I needed a FAT :slight_smile:

Grab a Loop device:

$ sudo losetup -f
/dev/loop0

$ sudo losetup /dev/loop0 bone-debian-stretch-iot-armhf-2017-06-04-4gb.img

$ sudo kpartx -av /dev/loop0

$ ls /dev/mapper/
control loop0p1

$ mkdir disk
$ sudo mount /dev/mapper/loop0p1 disk/

This fails at my side.
I now wrote the sd card, and it boots, if I boot directly from sdcard (bypassing my old eMMC u-boot).
I may have forgotten to include an obscure ext4 option in my local kernel?

Am I right that the SoC can boot directly of an ext4? or is U-Boot
hidden in the first free blocks?

Kind regards,
Kurt

5

I confirm that the nbd way does not work with me.
I followed the losetup way, and then I can mount.
That was a hard lesson ...

Thanks for the help.

Kurt

6

> Hey,
>
> When I download sdcard images for the BBB, I verify that the sum is correct.
> after xzcat, I only find 1 partition in the image, which I cannot mount.
>
> Does this sound familiar.
> I cannot believe all images are bad, so it must be something wrong on my
> computer.
> I fail to imagine how xz can be wrong.

It's best to use losetup/kpartx to mount it:

Well, I used nbd with 'qemu-nbd -c /dev/nbd0 bone....img.
that should work the same.

$ unxz bone-debian-stretch-iot-armhf-2017-06-04-4gb.img.xz

$ sudo fdisk -l bone-debian-stretch-iot-armhf-2017-06-04-4gb.img
Disk bone-debian-stretch-iot-armhf-2017-06-04-4gb.img: 3.3 GiB,
3565158400 bytes, 6963200 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
Disklabel type: dos
Disk identifier: 0xd12441de

Device Boot Start End
Sectors Size Id Type
bone-debian-stretch-iot-armhf-2017-06-04-4gb.img1 * 8192 6963199
6955008 3.3G 83 Linux

Ok, 1 partition. I supposed I needed a FAT :slight_smile:

yeah, we've been using 1 partition by default for a couple years now..

Grab a Loop device:

$ sudo losetup -f
/dev/loop0

$ sudo losetup /dev/loop0 bone-debian-stretch-iot-armhf-2017-06-04-4gb.img

$ sudo kpartx -av /dev/loop0

$ ls /dev/mapper/
control loop0p1

$ mkdir disk
$ sudo mount /dev/mapper/loop0p1 disk/

This fails at my side.
I now wrote the sd card, and it boots, if I boot directly from sdcard (bypassing my old eMMC u-boot).
I may have forgotten to include an obscure ext4 option in my local kernel?

Am I right that the SoC can boot directly of an ext4? or is U-Boot
hidden in the first free blocks?

The bootrom, supports raw boot, so u-boot's stored inside the first
1MB of the drive.

Regards,

7

That’s an awesome set of command line tools I had never seen before. I had to install kpartx (Ubuntu 16.04) and reboot.
All works after that. rootfs even shows up in the GUI file browser.

Thanks!
Greg