So yeah, when I get mine I will let you know with the few consoles I have here right now if there are any issues.
I can test it on a SuperGrafx with Super CD-Rom 2, Duo-R with a region mod, Duo-R without region mod, a PCE Duo and a US Duo.
My old v2.2 (bad version) card failed on my Core Grafx II + SuperCDROM combo.
The replacement v2.3 (1st fixed version) works fine on the same system.
The new version also works on my PCE Briefcase with both original PCE and Core Grafx II, my Turbo DUO and my DUO-R.
But none of those have region-mods so I can't comment on that aspect.
I am mostly curious if it works correctly with the region modded Duo-R as I wired the 5v to the HuCard slot pin and not at the 7805.
There's a guy on KRIKzz's forum with a DUO-R that had to rewire his region-mod to get it's power from the 7805 input and not it's output ... but that's the single report that I've seen of problems with the newer v2.3/v2.4 card.
I have noticed that when it boots there is a pause with a white screen then the list loads up.
It could be a SD issue if it's stuck on a white screen.
That's definitely the normal behavior as the card's firmware loads the OS from the SD card on power-up.
You'll normally get an error screen displayed if the firmware has a problem reading the SD card.