location of ROM binary?

[sknebel]

https://www.sifive.com/blog/2018/09/06/an-open-source-release-of-the-freedom-u540-c000s-bootloader/ links to this repository as the location for a copy of the ROM contents, but there doesn't appear to be a non-source, binary file here?

[tmagik]

The binary slipped through the cracks (or maybe my .gitignore) on that one.

The file to be posted is:

shasum -a 256 bootrom.bin 
f9353bab5e826e937783c9ace7411375af9733c454d3d5f9f365509f2f7a4cdb  bootrom.bin

[zhuowei]

@tmagik Would it be possible to post the original file in addition to the hash?

[tmagik]

https://github.com/sifive/freedom-u540-c000-bootloader/tree/challenge/u540-c000-release

[tmagik]

So one conjecture I have heard floating around is that on the HiFive1, you cannot reliably read the MASK rom if you turn up the clock speed, and if this is the case on the HiFiveU as well, this would explain why I spent half a day trying to confirm (with no success) that what I'm posting is a byte-for-byte copy of what is in the ROM.

Extra bonus points (in my opinion, anyway), if you can propose, or better yet, show some code, for some reasonable method for the bootloader to attest to the code it actually ran such that we could verify it in Linux or the device tree.

[zhuowei]

@tmagik

you cannot reliably read the MASK rom if you turn up the clock speed ... I spent half a day trying to confirm ... that what I'm posting is a byte-for-byte copy of what is in the ROM.

I noticed that the fsbl code is responsible for increasing the clock speed of the main CPU; can one dump the bootrom from the fsbl before the clocks are increased?

[tmagik]

If the serial clocks are set right this seems like a very good idea (or memcpy it to a buffer and dump it later) Send me a patch and I will try it

…

On Fri, Sep 7, 2018, 7:54 PM zhuowei ***@***.***> wrote: @tmagik <https://github.com/tmagik> you cannot reliably read the MASK rom if you turn up the clock speed ... I spent half a day trying to confirm ... that what I'm posting is a byte-for-byte copy of what is in the ROM. I noticed that the fsbl code is responsible for increasing the clock speed of the main CPU; can one dump the bootrom from the fsbl before the clocks are increased? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#3 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AGAQECyplp95BjO-l_VrZ6CtOy1XQpL3ks5uYxVagaJpZM4We-1R> .

[zhuowei]

@tmagik Something like https://github.com/zhuowei/freedom-u540-c000-bootloader/tree/dumprom ? I don't have a u540, so I'm not sure if I'm doing this right.

[tmagik]

https://gist.github.com/tmagik/c5a09a0a470a8f248ffb17876e2b8342 https://github.com/tmagik/freedom-u540-c000-bootloader/tree/dumprom

…

On Sep 8, 2018, at 7:30 AM, zhuowei ***@***.***> wrote: https://github.com/zhuowei/freedom-u540-c000-bootloader/tree/dumprom