With recent development kernels from https://cgit.freedesktop.org/~agd5f/
(drm-next-4.19-wip, I think commit ddf74e79a54070f277ae520722d3bab7f7a6c67a) I
can consistently complete cold/warm boot on my 2400G, before it was 1 in 4~5
attempts.

I think unrelated to the above, I still have various asserts with stack traces
on the logs in the "write_i2c_retimer_setting" function in
"drivers/gpu/drm/amd/display/dc/core/dc_link.c". They seems to be all write
failures but they don't seem fatal.