That's because he also posted this video on reddit where it was discussed.
Edit : For reference https://www.reddit.com/r/3dshacks/comments/6xlgac/ntrboot_on_r4igoldcc_and_ards/?st=J7CBVDHT&sh=6851c677
Alright, tried it with ak2i_ntrcardhax_flasher.nds and keep getting this message
ChipID : 00000FC2
HW Rev: 46464646
well I don't know what to do with that information ^^
Devs are working on this card afaik, can't tell you how long it will take though. Just buy an acekard / r4i gold from nds-card if you want to get cfw as soon as possible.