That card is the sdhc version of the original wood r4. It shouldn't even be flashable since it's not a dsi/3ds card. In any event, it certainly isn't supported. However it might actually have a flashable bootloader since you managed to mess with it with ntrboot_flasher. Go ahead and make an issue here https://github.com/kitling/flashcart_core#requesting-support-for-a-new-cart and maybe they can get it supported in the future.