RAM load doesn't work for me

[tcal-x]

@swillner am I doing something wrong here?

I can't get RAM load to work. I'm building examples/riscv-blink with make LOAD_RAM_ADDR=0x10001000, and loading it with dfu-util -D riscv-blink.dfu. The first bytes of the .elf look good:

10001000 <_ftext>:
10001000:       23c0006f                j       1000123c <crt_init>
10001004:       17ab0f23                sb      s10,382(s6)
10001008:       1000                    addi    s0,sp,32
1000100a:       1000                    addi    s0,sp,32

When I try to load it, the fomu gets stuck in the write phase (rapid blue blinking) with this message from dfu-util:

Download        [                         ]   0%            0 bytesError during download get_status

or, dfu-util says it finished but the fomu is in the red error blinking mode.

I've tried it with different fomu and different foboot versions (v2.0.2, v2.0.3, and v2.0.3-55-ge928b86).

[swillner]

hmm, I had these kinds of problems when I used an address intersecting with currently used ram. Have you tried other addresses? I can also give it a try again with my setup. You directly start from a clean foboot flashed as bootloader and no other program flashed, right?

[tcal-x]

Hey, I think that's it. If I do make LOAD_RAM_ADDR=0x10001200, then it works. This is with v2.0.3 foboot.

[mithro]

Guess we should have more documentation around this?

[tcal-x]

Yep, we can update the doc to use something that works. Should we try to figure out what changed and causes 0x10001000 to no longer work?

[mithro]

Probably!

[tcal-x]

There are some symbols in bios.elf that now use locations above 0x10001000:

$ nm bios.elf | grep 10001
10001200 B _ebss
10001200 B _end
10001128 b out_buffer
100011a8 b previous_setup_packet
100011b4 b rx_buffer
100011f4 b setup_packet

[mithro]

@tcal-x - I agree with @xobs that we should put something into the foboot build script which checks that the bios doesn't use anything past the address we are giving for ram load.