Issue Running Ariane Co-Simulation Tutorial: Bootram File Loading Problem

Hi,
I hope this isn't too much of a beginner's question, but I ran into a problem while following the Ariane co-simulation tutorial.

I rolled all the repositories back to the December 2019 versions, when the tutorial was made: dromajo, ariane, verilator, etc. I was able to compile the project successfully, but I couldn't get it to run.

In step 4 of the tutorial, there's a patch to add a bootram file to the Ariane core, which looks like this:
```
// sync with dromajo
if ($value$plusargs("checkpoint=%s", f_name)) begin
hex_file = $fopen({f_name,".bootram.hex"}, "r");
while (!$feof(hex_file)) begin
num_bytes = $fscanf(hex_file, "%d %h\n", address, value);
$display("%d %h", address, value);
mem[address] = value;
end
$display("Done syncing RAM with dromajo...\n");
end else begin
$display("Dromajo error: provide path to a checkpoint.\n");
end
end
```
I couldn't load the file for two reasons:

1. There are no .bootram.hex files generated—dromajo only produces .bootram files when saving a checkpoint.
2. The .bootram files appear to be binary, but (if I'm understanding SystemVerilog correctly) $fscanf seems to only support reading text files.
Could you clarify if there's a step missing in the tutorial or if any additional modifications are needed to process the .bootram files correctly?

Thank you for your help!

Start with step 4 of the Ariane co-simulation tutorial and the shown bootram-loading patch. Compare the .bootram files produced by dromajo checkpoints with the SystemVerilog $fscanf-based loader; the issue is resolved when the tutorial documents or provides a working way to load the checkpoint memory file.

Written by the indexing model from the issue text.