External Booting for Kobos (aka boot from external SD card)

pazos · 08-01-2017, 04:27 PM

Hi. Something that I find useful and can't find here in mobilereads:

This works for Kobo models:

Tested (Touch, Aura HD)
Non tested (Glo, Aura, Aura H2O)
Non working (lack of SD mainly): Mini, Glo HD, Aura One ...

The bootloader has a recovery mode that is triggered with button combination --- WITH the device turned off -- :

For Kobo Touch: home + power
For other models: frontlight + power

Using those key combos the device will boot with the first partition of the external SD card as the rootfs. The filesystem must be ext2/3/4 for this partition.

You can boot debian or any other armhf distro with this method!
Have fun...

Issues:

- if you run the stock OS with the external SD plugged in it will display a warning message about invalid format and sometimes will atempt to format the partition as vfat. So you MUST power off your device and extract the external SD card before running the stock OS.

- the recovery script that uboot runs seems to take more time than normal boot. Very noticeable (2-3seconds). This means that external booting takes more time than internal booting.

sahbi · 08-14-2017, 02:48 AM

Thanks for this usefull tip, but could you please elaborate how to do that for an (old)H2o, there's only a power button there, so how to trigger a button combination?
Power button + ?????

davidfor · 08-14-2017, 03:49 AM

Quote:

Originally Posted by sahbi

Thanks for this usefull tip, but could you please elaborate how to do that for an (old)H2o, there's only a power button there, so how to trigger a button combination?
Power button + ?????

The button combinations mentioned are those used to trigger a factory reset. It probably means these button combinations trigger alternate boot sequence: external SD card and then the recovery partition. If that is right, then using the external factory reset method for the one-button devices is what you want. For the Aura H2O, this is holding the power button down and tapping both bottom corners until something happens.

Disclaimer: The above is an educated guess. It might just factory reset your device. Take a copy of the data on the shared partition before trying.

tshering · 08-14-2017, 03:53 AM

You could try this

Quote:

Originally Posted by sti

with the external SD plugged in power-on the H2O and keep the power button pressed

lohtse · 08-14-2017, 04:35 AM

could you provide links to the distros etc :-)

pazos · 08-18-2017, 07:59 PM

Quote:

Originally Posted by davidfor

The button combinations mentioned are those used to trigger a factory reset. It probably means these button combinations trigger alternate boot sequence: external SD card and then the recovery partition..

Yes! If sdcard is present root is /dev/mmcblk1p1 (first partition on external sdcard) instead of /dev/mmcblk0p2 (second partition on internal sdcard - the recovery partition).

Quote:

Originally Posted by lohtse

could you provide links to the distros etc :-)

sorry but no ready-to-go binary distros for armhf. slackwarearm should work but is soft-float so you'll loss the ability to run other software made for kobo. Here is a link to the mini-rootfs ftp://ftp.arm.slackware.com/slackwar...01Jul16.tar.xz

I would suggest to install debian instead. You can install it via debootstrap/multistrap, there are a lot of guides online for that task.

I think I can legally share a binary copy of debian armhf distro targeted for kobos, but sadly I can't distribute the kernel, kernel modules and fw present on kobo devices, which are needed to do something useful with the device.

BaronPampa · 02-23-2019, 03:39 AM

Has anyone confirmed it works on Kobo Touch N905, the one without internal SD card? It seems like a perfect way to get Linux without risking bricking the device, as it doesn't touch the internal memory. All I've managed to do is factory reset mine a few times. I've tried:

-formatting a card as ext4 and using dd with Marek's Debian image from https://www.mobileread.com/forums/sh...d.php?t=222123
-formatting a card as ext3 and using dd with https://www.mobileread.com/forums/sh...d.php?t=203986
-unpacking the slackware pazos provided one year ago. I've just unpacked it on ext3 formatted SD card

If nobody can confirm/deny it works on N905 mk3, I'd be grateful for instructions on how to create a working SD card for one of the other devices, so I can adapt it to mine.

08-01-2017, 04:27 PM	#1
pazos cosiñeiro Posts: 1,271 Karma: 2200049 Join Date: Apr 2014 Device: BQ Cervantes 4	External Booting for Kobos (aka boot from external SD card) Hi. Something that I find useful and can't find here in mobilereads: This works for Kobo models: Tested (Touch, Aura HD) Non tested (Glo, Aura, Aura H2O) Non working (lack of SD mainly): Mini, Glo HD, Aura One ... The bootloader has a recovery mode that is triggered with button combination --- WITH the device turned off -- : For Kobo Touch: home + power For other models: frontlight + power Using those key combos the device will boot with the first partition of the external SD card as the rootfs. The filesystem must be ext2/3/4 for this partition. You can boot debian or any other armhf distro with this method! Have fun... Issues: - if you run the stock OS with the external SD plugged in it will display a warning message about invalid format and sometimes will atempt to format the partition as vfat. So you MUST power off your device and extract the external SD card before running the stock OS. - the recovery script that uboot runs seems to take more time than normal boot. Very noticeable (2-3seconds). This means that external booting takes more time than internal booting.

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08-14-2017, 02:48 AM	#2
sahbi Enthusiast Posts: 42 Karma: 50 Join Date: Oct 2011 Device: Sony:psr 650 , KOBO:aura h2O, KOBO:Aura One	Thanks for this usefull tip, but could you please elaborate how to do that for an (old)H2o, there's only a power button there, so how to trigger a button combination? Power button + ?????

08-14-2017, 04:35 AM	#5
lohtse Groupie Posts: 197 Karma: 38050 Join Date: Oct 2013 Location: Anywhere I am sent!!! Device: Kobo Touch	could you provide links to the distros etc :-)

02-23-2019, 03:39 AM	#7
BaronPampa Junior Member Posts: 2 Karma: 10 Join Date: Feb 2019 Device: Kobo Touch N905	Has anyone confirmed it works on Kobo Touch N905, the one without internal SD card? It seems like a perfect way to get Linux without risking bricking the device, as it doesn't touch the internal memory. All I've managed to do is factory reset mine a few times. I've tried: -formatting a card as ext4 and using dd with Marek's Debian image from https://www.mobileread.com/forums/sh...d.php?t=222123 -formatting a card as ext3 and using dd with https://www.mobileread.com/forums/sh...d.php?t=203986 -unpacking the slackware pazos provided one year ago. I've just unpacked it on ext3 formatted SD card If nobody can confirm/deny it works on N905 mk3, I'd be grateful for instructions on how to create a working SD card for one of the other devices, so I can adapt it to mine.

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