Leo soldered a USB adapter onto the card’s pinouts. The V20A revision, he’d read on a long-dead forum, had a secret: a debug mode accessible via a register write that Ralink never documented. It could bypass the MAC layer entirely and talk directly to the baseband processor. Raw. Unfiltered.
The RT3090BC4 V20A driver is not in the Linux kernel mainline. It’s not on GitHub trending. It’s a footnote, a relic, a broken thing held together by one engineer’s promise and another’s obsession. ralink rt3090bc4 v20a driver