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Aydan · 10-01-2014, 08:50 AM

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

10-01-2014, 08:50 AM	#20
Aydan Connoisseur Posts: 87 Karma: 2975 Join Date: Jan 2012 Location: Germany Device: Kobo Touch	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 Last edited by Aydan; 10-01-2014 at 08:53 AM.