Kobo H2O Hackability

[robko]

Originally Posted by Mivo

Slightly unrelated to the hackability, but can the light be completely turned off through a software toggle?

No software toggle yet. Not sure just how low it will go with slider on the H2O, but it might get it down to zero. But you can't from OFF to back ON at same level as originally at with one press. I suggested this would be a good thing to have, but it hasn't made it into the firmware yet.

[ManDay]

Originally Posted by PeterT

Examination of any / all scripts present on the device don't show sign of it either.

For what it's worth, scripts or the software on the current device wouldn't have anything to do with it, since the actual firmware resides on some EPROM outside the system. Pretty much as there aren't any files containing the BIOS on an actual computer, either.

I think it's a rather sure bet that such a facility has been included in the device for Kobo to handle fatal, warranty covered software breakages on returned devices efficiently. We just have to find it.

[davidfor]

Originally Posted by ManDay

For what it's worth, scripts or the software on the current device wouldn't have anything to do with it, since the actual firmware resides on some EPROM outside the system. Pretty much as there aren't any files containing the BIOS on an actual computer, either.

I think it's a rather sure bet that such a facility has been included in the device for Kobo to handle fatal, warranty covered software breakages on returned devices efficiently. We just have to find it.

Kobo do have a function for fatal, or at least near-fatal, software problems. All the devices can do a factory reset by pressing the appropriate combination of buttons. If this doesn't revive the device, booting from the external card is unlikely to help. And as most of the devices can be opened and the internal SD card replaced, if the factory reset doesn't work, this can be done. But, from a cost point of view, it is probably better for Kobo to just replace the device.

[ManDay]

Call it speculation, but I think since the devices run a firmware one way or another, it would be silly to not program that firmware so that a specially designed SD-card automatically overwrites the complete internal memory. Even a single, unfortnuate bit-flip in the kernel may render the device unbootable and, as PeterT pointed out, opening it will most likely damage the seal permanently (let alone being a 30 minute task for an employee), throwing it away would be the only alternative.

[Aydan]

The factory reset is kicked off by a modified uboot htat reads the state of the PWR switch and home button (depending on the model), which changes the kernel cmdline and boot partition to boot into the rescue partition. So you still need a working SD-card with a working u-boot, kernel and rescue partiton. If one of these is trashed, you're done.
The CPU itself will only boot from the internal SD-card/eMMC and load the uboot from a fixed position in the flash memory. There's no extra NVRAM for a bootloader or BIOS (which is a PC thing, not an ARM thing).
Is is possible to patch uboot to boot from the external SD card, but uboot still needs to run from the internal SD/eMMC.
For factory programming/recovery they'll use JTAG to access the CPU and either load a program into memory or directly access the eMMC so Kobo itself has no use for this type of recovery function.

Regards
Aydan

[ManDay]

Thanks for the outstanding explanation Aydan!

[Aydan]

Glad I could help.

[downeaster59]

I have an Aura HD, and I have used the hack (from another thread in this forum) where you can run Android 2.3 (yeah, it's old) from the microSD card of the Aura HD and a few other Kobo e-readers. I wonder how hard it would be to do this for the H20. I don't know yet if the H20 is enough of an upgrade to warrant me buying it, but I'm curious.

[j.p.s]

Originally Posted by PeterT

Just remember though; while people have opened other devices to restore the SD card in case of corruption, I'm not sure what effect on water-tightness opening the H2O would have.

And what effect on opening water-tightness will have?

[PeterT]

Originally Posted by j.p.s

And what effect on opening water-tightness will have?

One of the selling points on the H2O is it's water-proof certification.

All I am saying is who knows what effect opening the case of the H2O will have on that water tightness.

[j.p.s]

Originally Posted by PeterT

One of the selling points on the H2O is it's water-proof certification.

All I am saying is who knows what effect opening the case of the H2O will have on that water tightness.

That is what I understood.

What I asked is whether the new water tightness will affect the ease of opening the case.

[PeterT]

I have NO idea.... Get one and experiment.

[robko]

Originally Posted by Mivo

Slightly unrelated to the hackability, but can the light be completely turned off through a software toggle?

Now that I've got my H2O, I can confirm that the light can be completely turned off at the zero percent setting. Tested by turning to zero, going into a pitch black room, waiting for a bit for my eyes to adjust, and if I had set the device down I would not be able to tell where it was. So you can't toggle on/off to the same level with one touch, but it does go to off (not just really, really dim) to my eyes.

[Mivo]

Thanks, Robko, that is fantastic news!

[doxallday]

Originally Posted by robko

Now that I've got my H2O, I can confirm that the light can be completely turned off at the zero percent setting. Tested by turning to zero, going into a pitch black room, waiting for a bit for my eyes to adjust, and if I had set the device down I would not be able to tell where it was. So you can't toggle on/off to the same level with one touch, but it does go to off (not just really, really dim) to my eyes.

Sweet. I'm expecting mine in less than a week, can't wait to begin a marathon.
By the by, how many of you employ installation of new fonts? Is there an advantage to the default set out of the box? If so, which ones would you recommend?