[LEDE-DEV] Mikrotik RB411AH sysupgrade issues

[Sergey Ryazanov]

Hello,

I tried to install latest LEDE to RB411AH board. Sysupgrade worked
fine, but device now do not boot at all. Bootloader claims that it
could not find kernel :(

I tracked down the situation and found that the kernel partition image
generated with assumption that any 64Mb NAND flash IC consists of
pages, the size of which is 512 bytes with an 8-byte spare area. But
my board equipped with Toshiba NAND flash, which consists of pages,
the size of which is 2048 bytes with an 64-byte spare area.

Even worse, after such reflashing with the corruption of the page
structure, kernel starts thinking that pages are bad and they could
not be used anymore. So I had to install vendor's firmware back with
help of vendor utility to recover pages structure.

To fix this I see several solutions:

1. Generate more images, one for each combination of flash and page
sizes (e.g. xxx-64m-512-sysupgrade.bin, xxxx-64m-2048-sysupgrade.bin)
Pros: quick realization, no sysupgrade code modification
Cons: exponential growth of number of images, unusable due to endless
mess with this set of images.

2. Inclusion of multiple kernel partition images to one firmware image
for sysupgrade (e.g. xxx-64m-sysupgrade.bin will contain
kernel-512.bin, kernel-2048.bin, etc.).
Pros: there are no mess with set of images
Cons: useless growth of sysupgrade image

3. Create utility, which will generate yaffs image on the fly during flashing
Pros: avoid mount operation during flashing procedure
Cons: a lot of work, rootfs growth

4. Return the YAFFS support back to the kernel, place kernel as
regular file to sysupgrade image, mount kernel partition during
sysupgrade, just copy kernel there and let YAFFS driver do its work.
Pros: quite universal solution, ability to access yaffs partitions at any time
Cons: small kernel growth, incompatible sysupgrade code modification,
mounting of the partition during flashing

Personally I like last solution, and if there are no objection then I
will prepare patches in few days.

-- 
Sergey