How to boot uboot via mfgtools/uuu?

[minosimo]

Hello, I attempted to install postmarketos on my Libra 2 H2O, and some mount issues during flashing ended up wiping the emmc, or at any rate corrupting the partition table. As described on the pmos wiki, it now shows up as

hiddev96,hidraw2: USB HID v1.10 Device [   NXP    SemiConductor Inc  SE Blank 6SLL] on usb-0000:00:14.0-3/input0

I have been trying to learn how to use uuu to get uboot working again, but it is proving difficult. uuu seems to mostly be used to flash pre-built images, which of course wouldn't exist for the kobo.

According to the wiki, it should be possible to get back into uboot from this mode.

Before attempting the pmos install, I mounted the emmc over usb as described in the wiki and did a dd image dump, though I haven't found any way to make use of it yet.

My first instinct was to try to flash the full emmc image using uuu, but that doesn't seem possible. I'm now rather of ideas and any pointers in the right direction would be much appreciated.

Should I be trying to build uboot, package it into a uuu compatible image, and flash that? There's 25MB of free space before the first partition in the dd image, which I'm guessing is where uboot lives, is that correct? Should I be trying to convert that to something usable by uuu? Or something else?

Thanks!

[pazos]

Hi. Not familiar with uuu but quite familiar with low level things on kobos a few years ago. Hope these things are still relevant.

Based on the pmos wiki you linked it seems that uboot environment is at offset 768, so it is safe to assume that uboot goes first, from 0 up to 768.

I would try to boot that uboot from the backup you already have, just make a copy with the first chunks:

dd if=backup.img of=uboot.img bs=128k count=6

and try to load that with uuu

uuu -b spl uboot.img

You don't need to care about u-boot enviroment at this point, it will use the one that's compiled in case it fails to load it from disk.

[pazos]

Or

dd if=backup.img of=uboot.img bs=128k count=4

in case uuu or the downloader mode refuse to boot from a image with padded space.