Hey there,
I have a tolino shine 5 (same as kobo clara BW) and just played around with it. I came here to share my findings. They are valid from firmware 5+, but some parts seem to be there before already.
Beware: The following commands can brick your device _permanently_! Use at your own risk and own understanding. Also, you might accidentally hard reset your device deleting _all_ data!
Fastboot:
Device is fastboot enabled. Accessing is a little bit tricky:
* Turn device off and wait a moment to be sure it's off.
* Unplug the USB cable
* run your fastboot command like `fastboot oem readlkver` already, it will wait for the device
* Turn device on, keeping power button pressed
* very shortly after (within a few tenths of a sec) plug in the USB cable
* LEDS should flash very quickly.
* Keep power button pressed a bit longer, you'll see fastboot working. Feel free to release power button now.
To run a second fastboot command, unplug and replug USB cable. The device stays in fastboot mode.
With `fastboot reboot` you'll boot to bootloader which will overwrite system partition or maybe even hard reset your device!. To actually reboot, long-press the power button.
* `fastboot flash system_a path_to_img` flashes system
* `fastboot flash boot_a path_to_img` flashes kernel
You should not try to flash uboot or tee or bl2 - breaking any of those partitions renders fastboot unusable.
I went further and flashed the spa-colour kernel on my spa-bw device (via fastboot - so I knew if it flashed something I could revert by flashing the old one
).
Actually, flashing via fastboot is way quicker than using the update.tar method.
I compared the device trees of colour and bw before: They _seemed_ to be equivalent despite colour having a dual core, 2 GHz CPU (bw: single core, 1 GHz). I did not see that the touch screen controller is initialized with a different register setting - now my touch screen is inverted on the X-Axis and I didn't bother finding a way to reverse (I guess flashing back old kernel would work).
Unfortunately, my second CPU does not come up:
Code:
lscpu
Architecture: armv7l
Byte Order: Little Endian
CPU(s): 2
On-line CPU(s) list: 0
Off-line CPU(s) list: 1
Vendor ID: ARM
Model name: Cortex-A53
Model: 4
Thread(s) per core: 1
Core(s) per socket: 1
Socket(s): 1
Stepping: r0p4
CPU max MHz: 2000.0000
CPU min MHz: 600.0000
BogoMIPS: 15.60
Flags: half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm aes pmull sha1 sha2 crc32
Trying to put it online logs a kernel error message -22 (Invalid argument).
I have seen a `/proc/cpuinfo` dump of a dual core tolino vision colour which also only showed _one_ cpu core - I expect there could be a problem with the kernel that Kobo might not have noticed themselves