loading u-Boot in memory instead of flashing it

Question

In my ARM based custom board, I flash u-boot to NAND whenever I do changes on that. (putting some debug statements/modification). Is there any way to directly load the uboot ima

Answer 1

Just take in mind (be care of) the hardware that you are configuring in your modified U-Boot. U Boot is intended to initialize critical modules, some of them are not able to be re-configured on the fly or they may not performe as if they were initialized/configured at startup.

Answer 2

If your Target board support network booting, you can load uboot image from host machine to RAM through network.

Answer 3

The problem here is that what you are trying to do goes against the philosophy of what a bootloader is. Most processors require that code starts from Flash. That code is called a bootloader. That is what U-boot is.

However, if you want to modify U-boot so that it is not a true bootloader, then you can do whatever you want. It's just software. But don't expect any mainline support for the above reasons.

Answer 4

It should be possible, if the U-Boot image you want to run has startup code that allows running it from arbitrary addresses. Whether or not that is the case for your board I can't tell.

If the startup code begins by copying the code section from the current (PC-relative) address to the final execution address (usually this is preceded by a check that these areas don't overlap), then you can load the .bin file to any address in RAM, and invoke it using go.

The second obstacle I could see would be unconditional RAM setup code at the beginning, which a number of boards have.

Answer 5

You can use usb boot. TI and Freescale provides their usb boot utilities. I don't know about other vendors.

Answer 6

It wasn't possible in 2004, at least.