Hi,
I am working on my own fork, and I do see other results. I did not change the JTAG interface handling (yet) and is based on GPIO. I reach the following speeds:

Loading section .init, size 0x236 lma 0x8000000
Loading section .text, size 0x3522 lma 0x8000240
Loading section .sdata2._global_impure_ptr, size 0x4 lma 0x8003764
Loading section .data, size 0x70 lma 0x8003768
Start address 0x800015c, load size 14284
Transfer rate: 12 KB/sec, 840 bytes/write.

nice!

@Micha Hoiting Where did you optimize compared with this resp?

Hi,
Here is my fork https://gitee.com/michahoiting/rv-link for my own project.
You can try it out, but I did not do any thing on optimization.
Maybe I can help to find out why your speed is only 3KB/sec?

I tested it again, it's totally ok now. Thank you!