After the issues with the vertical alignment and sound output with the HDMI encoder used by gbaHD, I went in search of an alternative encoder. I've been working to integrate hdl-util's HDMI 1.4b encoder; when I tested their demo I got sound and although the vertical alignment issue persisted, the much smaller vertical sync size means that it's far more likely that the GBA video would appear fully on my TV.

One idea for the vertical sync is to hold the output on the GBA clock on startup for a few cycles. It'd be a bit of a blunt workaround but may help for my particular build and setup.

I haven't yet got a workable output, which I think is down to getting the timings just right. The GBA video needs to lead the HDMI video, but if it's too fast either the line buffer will overfill or the GBA will do a frame refresh before the HDMI video has been drawn. I need to work on a model of the video timings so I can find the right balance.

Updates from here on will probably be a bit slow as I take it a bit easier on this project. And if new Analogue Pocket pre-orders come up before I've completed this, I'll probably mothball the project. Hopefully I can get it working before that!