Query on RISC-V booting ABI

Ivan Velickovic i.velickovic at unsw.edu.au
Fri Nov 21 03:00:46 CET 2025


Hello everyone,

My understanding of the general RISC-V bootflow ABI is that each boot stage provides the hart ID and DTB
in a0 and a1 respectively. From [1] I can see that U-Boot also adheres to that.

For my use-case, I am typically booting my OS/application with U-Boot via the `go` or `bootelf` commands.
I believe that currently these methods do not adhere to this ABI, and I’m wondering if someone could clarify
whether that is a mistake or intentional?

I can see that for `bootm` for Linux images for example, the ABI is preserved [2].

Thank you,
Ivan

[1]: https://docs.u-boot.org/en/latest/arch/riscv.html
[2]: https://github.com/u-boot/u-boot/blob/2bc0715b558fa1ac5c88b11e250740b16a905837/arch/riscv/lib/bootm.c#L100.



This email and any files transmitted with it may contain confidential information. If you believe you have received this email or any of its contents in error, please notify me immediately by return email and destroy this email. Do not use, disseminate, forward, print or copy any contents of an email received in error.



More information about the U-Boot mailing list