Hi John,
Hi Lukasz,
On Tue, Apr 11, 2017 at 12:40 AM, Lukasz Majewski lukma@denx.de wrote:
Hi John,
Instead of having 2 builds of u-boot, one which defaults to fastboot and one for normal booting, is it possible to have one u-boot binary and a separate environment piece (especially for bootcmd, but maybe also for some scripts)?
If I might ask - where your envs are stored? Do they have a separate area in NAND or eMMC memory?
If yes, then I suppose that you also have the possibility to write data to this memory in the production?
The production redundant environment will have its own area in eMMC. The environment could be written to the eMMC from the development host after running fastboot or ums in u-boot, but the question is how fastboot/ums gets run when starting with a completely blank, freshly soldered, non-partitioned board.
I've already used two approaches (with TI SoC):
- Use "factory" SD card (if the slot is available) with tunned u-boot (by altering envs)
- Use serial port (you mentioned that you want to talk with the board with 'expect') to transfer SPL(MLO)/u-boot
The above option though is relatively slow, but at least for me it worked reliably.
- Maybe you can boot from USB stick (I don't know what is your target SoC).
If yes (again) then maybe it would be better to only adjust (and replace) the default environment on board?
For example:
- You extract envs by using the scripts/get_default_envs.sh -
modify it and then use mkenvimage to produce new env image.
- You store u-boot (with NAND/eMMC not programmed) to your device.
This u-boot has default environment with instructions for flashing.
- You flash your final envs prepared in point 1.
It seems that flashing the environment binary, or any other piece, first requires something running on the target to accept the bits and flash.
Yes, correct.
Setting CONFIG_BOOTCOMMAND at compile time will do, but ideally, I can use the same bootloader binary and decide the bootcmd at deploy time.
Personally, I would go for some script file (like boot.scr), which then would be imported to u-boot envs. That file can be also easily replaced at factory time, by just changing the file content.
Thanks, John
Best regards,
Lukasz Majewski
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