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FoolishMooon / cm-paz00

Automatically exported from code.google.com/p/cm-paz00
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Can't downgrade to an old release #14

Closed GoogleCodeExporter closed 8 years ago

GoogleCodeExporter commented 8 years ago 
I've just upgraded my AC100 to try the new uBoot and CM10 ROMs --- they work 
well, but I've decided that CM10.1 just too slow on the AC100 and so wanted to 
downgrade to the CM9 I was previously using. Unfortunately the CM9 ROM isn't 
compatible with uBoot. Attempting to install the update via the CM10.1 recovery 
writes the Android boot img to the LNX partition, and of course uBoot doesn't 
know what to do with that.

I did try extracting the kernel and initrd from the CM9 boot image and manually 
placing them in the LNX partition, but they don't load (the kernel complains 
about an invalid initrd). And I've tried booting the CM9 system image off the 
CM10.1 kernel and initrd and of course it doesn't work.

I also tried restoring the NV partition table based on the deprecated 
installation instructions. That was possible, but since the old NV bootloader 
had been overwritten it didn't do me any good.

It'd be really nice to have the CM9 ROM updated to work with uBoot...

Incidentally, while trying to restore the NV partition table I trashed uBoot. 
Trying to put uBoot back on using the recovery I found that the switch-to-uboot 
script explicitly checks to see whether the LNX and SOS partitions contain 
valid boot images, and refuses to proceed if they don't. I had to comment this 
test out to get my device working again.

Original issue reported on code.google.com by david.given@gmail.com on 13 Nov 2013 at 12:50

GoogleCodeExporter commented 8 years ago 
There is no simple downgrade and no plans for it, fastboot and old versions 
which work with him not supported any more. Simply restore your full backup 
with nvflash rawdevicewrite.

Original comment by zombah on 15 Nov 2013 at 2:54