Subnostr

Hello. What do these two traces go to?

#m=image%2Fjpeg&dim=1080x1440&alt=A+small+USB+device+that+has+two+traces+from+a+couple+of+pins+highlighted.+They+go+to+two+header+pins+that+appear+to+go+through+to+the+other+side+of+the+board.&blurhash=_MI5D1Ri%7E8V%5DtRaMNL%7EWs.NIf%2BRjWCs.%3FFj%5DIpt6WDoxobWSW%3BWGV%5Bo0oej%3FR%24j%5Bs%3BWUk9jbWBohofadWUkCbFj%5DRRWUt6ogWBbFazt8fPRifks%3Be%3BWCV%40WCozkAafj%5DbX&x=9ebdf1cd1b64c981e38a654c8a21a7257b3d9d599b984e7fdacf60b8dbb5105a

Oh, just some header pins. I wonder what those are for...

#m=image%2Fjpeg&dim=1080x810&alt=The+opposite+side+of+the+previously+pictured+USB+device.+Here+we+can+see+that+it+is+a+Signet+v1.3+device.+From+this+angle+we+can+see+that+it+is+two+male+header+pins+that+were+connected+to+those+traces+from+the+other+side+of+the+PCB.&blurhash=%23HECwb4.-VICxtIoxtbIR%23XUIXM%7BoeRkofofaxs%3A%7EAaOSekRR*xuR*n%2CnnMxRjWWjvofj%5BaxWBkC-mV%7BS4koj%5DaKj0kSSdWAocWFkDoLV%40ozkVWBtRWTRRWEj%3Dayj%3Fj%5Boe&x=abd52f7ff9d8e43e76108f32797f1a12dae604bc8bef43b1f17a4e256062ed0f

Reply to this note

Please Login to reply.

Discussion

Dr. Hax 1y ago

Spoiler: it's UART pins. I'm going to see if I can get runtime debug messages from the device.

This should help me see if the commands are ever making it through Qubes 4.2 and being received by the device.

I know I am not getting any replies, but I can't tell if it's filtering on the way to the device, or on the way back (or both!).

mark tyler 1y ago

I was gunna guess an LED / Button with UART being third 🫂

Dr. Hax 1y ago

Third time is a charm!

mark tyler 1y ago

Yeah that should have been my first since the pins are neighbors

Autumn Sun ☀️🌘☯️ 1y ago

Signet 1.3?

Are those for an external antenna?

Dr. Hax 1y ago

Good guess, but no. There's no wireless anything in these devices. It's how people can be confident that if it didn't leave the devicr via USB, then it didn't leave the device at all.

This makes security auditing easier since there's only one code path to investigate.