[Arm-netbook] http://rhombus-tech.net/allwinner_a10/a10_boot_process/

[Henrik Nordström]

Sorry for topposting. Posted from my mobile.

boot0 and onwards is clearly loaded from the boot media/flash. boot0 first sets up the basic hardware configuration so DRAM memory access etc works. Then loads boot1 from somewhere into ram.

I would think boot1 is really the second part of boot0, after the first page.

Only BROM is in ROM. Plus bootstrap pins telling brom if it should look for sdcard, nand or usb fel mode for recovery.

It would be excellent if boot0 & boot1 sources can be published, or at minimum the boot0 hardware header specification and checksum method, allowing boot0 to be reconfigured in an open & portable manner. If sources can not be published (but hardware header can) then at least boot0&1 binaries licensed under a permissible license allowing unlimited redistribution of both original and modified versions.

My understanding is that boot.axf (and boot0.axf) is u-boot or similar mostly generic bootloader, with all hardware setup separated out in boot0/1.

Many other SoC uses similar boot method, with a master boot record from boot media configuring basic hardware and then loading the rest.

If boot0/1 can not be published to an acceptable degree then the other option for this project to be viable is to add a small external serial prom for these (i assume A10 can also load boot0 via SPI?). But that adds to the bom and looses a bit of the flexibility of the product and may not be suitable for the mass market target. But should be possible to use same board just leave the rom position unpopulated.

Regards
Henrik

----- Ursprungsmeddelande -----
> tom, you're a star - thank you for creating the boot process page.
> 
> question: boot.axf, its source code is available?
> 
> if so, then the a10 boot process isn't actually "closed", it's more
> "standard practice".   those boot0 and boot1 bits, they're ROM'd aren't
> they?   that's considered to be ok.
> 
> l.
> 
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