U-Boot UMS on APF & OPOS
From ArmadeusWiki
This page gather instructions for using U-Boot's USB Mass Storage gadget mode (or UMS) usage on APF6 and OPOS6UL(NANO). This mode allows you to flash rootfs images bigger than the available module RAM, ex: > 200MBytes on the OPOS6UL(NANO). Indeed run update_rootfs script uses RAM to store images while uploading from TFTP, which can be short for big rootfs. UMS also allows you to backup your rootfs on your Host.
- First, keep your USB debug cable and connect a second USB cable on APF6_Dev or OPOS6ULDev's OTG port.
- Under U-Boot type:
BIOS> ums 0 mmc 0 UMS: disk start sector: 0x0, count: 0x760000 |
- On your Host computer you should see the eMMC partition like a standard USB key.
$ dmesg | tail [...] [26828.348088] sd 13:0:0:0: [sdc] Mode Sense: 0f 00 00 00 [26828.348395] sd 13:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [26828.354177] sdc: sdc1 sdc2 [26828.356782] sd 13:0:0:0: [sdc] Attached SCSI disk
Here the device is /dev/sdc and all partitions have been automounted by the Host:
[26830.002168] EXT4-fs (sdc1): mounting ext2 file system using the ext4 subsystem [26830.054358] EXT4-fs (sdc2): mounting ext2 file system using the ext4 subsystem [26830.078638] EXT4-fs (sdc2): warning: mounting unchecked fs, running e2fsck is recommended [26830.114382] EXT4-fs (sdc2): mounted filesystem without journal. Opts: (null) [26830.135564] EXT4-fs (sdc1): warning: mounting unchecked fs, running e2fsck is recommended [26830.268450] EXT4-fs (sdc1): mounted filesystem without journal. Opts: (null)
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Warning: Before doing the following procedure, be sure that your device name is correct. You can erase all your Host datas if you do it wrong !!! |
- The rootfs is under the sdc2 and is named "ROOTFS". On your debian/ubuntu Host it might be auto-mounted under /media/usb1, if no other USB key is present on system and if you activated auto-mounting.
$ ls /media/usb1/ bin boot dev etc home init lib lib32 linuxrc lost+found media mnt opt proc root run sbin sys tmp usr var
- To flash entire rootfs, first erase all files on this partition:
$ sudo umount /media/usb1 (if partition is auto-mounted) $ sudo mkfs.ext4 -L ROOTFS -O ^64bit,^metadata_csum,uninit_bg /dev/sdc2
Update your rootfs
- Then, you have 2 methods to update your rootfs:
| tar method | dd method |
|---|---|
$ sudo mkdir /tmp/rootfs $ sudo mount /dev/sdc2 /tmp/rootfs
$ make shell_env $ . armadeus_env.sh $ sudo tar -xvf $ARMADEUS_ROOTFS_TAR -C /tmp/rootfs
$ sudo umount /tmp/rootfs/ $ sync |
$ sudo dd if=/tftpboot/xxx-rootfs.ext4 of=/dev/sdc2 (replace xxx with the name of your module) |
- Once finished, you can kill the U-Boot's USB gadget process with a Ctrl-C:
BIOS> ums 0 mmc 0 UMS: disk start sector: 0x0, count: 0x760000 CTRL+C - Operation aborted BIOS>
Backup your rootfs
$ sudo dd if=/dev/sdc2 of=/home/xxx/rootfs_xxx.ext4 (takes time ;-) )
- check if it succeed:
$ sudo mount -o loop /home/xxx/rootfs_xxx.ext4 /media/mmc/ $ ls /media/mmc/boot/
Troubleshots
- UMS was reported not working on Windows 7/8 hosts with Virtual Box Ubuntu 15.04 emulated machines...
