docs: add images

README.md

@@ -8,7 +8,7 @@ It enumerates as a standard serial device (e.g., /dev/ttyACM0 or COMx).
 
 PCB [here](https://git.ayau.me/mira/mhardware/src/branch/master/hp3478a-ch32-ext)
 
-![PCB](./img/IMG_20251130_023748.jpg)
+Photos in [img/](./img/) and the [demo video](./img/feats.mp4)
 
 ## Menu System
 
@@ -42,6 +42,7 @@ HP3478A Internal USB-GPIB 1.2.0
   ++eor <0-7>       Read Stop:  0:CRLF ... 7:EOI-Only
   ++eot_enable <B>  Append extra char to read output
   ++eot_char <dec>  The char to append
+  ++dmm_loop <0|1>  Toggle HP3478A loop, if it conflicts w/ GPIB bus
 
 [System Configuration]
   ++config          List all configurable parameters
@@ -131,7 +132,6 @@ Now your dBm feature will use 600 ohm ref instead of 50.
 
 ## Known Issues
 
-1.  I did NOT use the brain when routing the USBLC6. Either have to DNP the IC and jumper the data lines, or rely on the software hack to check USB `SUSPEND` to guess if the host is connected. I do the latter, works but meh.
+1.  I did NOT use the brain when routing the USBLC6. Either have to DNP the IC and jumper the data lines, or rely on the software hack to check USB `SUSPEND` to guess if the host is connected. I do the latter, works but meh. VBUS detection would be nicer.
 2.  The buzzer is **not on a hardware TIM pin**. It's on a generic GPIO... This means it can't be hardware/timer PWMed. Instead, the firmware is firing a TIM IRQ thousands of times a second just to manually toggle the pin in the ISR..
 3.  There is a microSD card footprint on the board. The fw does absolutely nothing with it. Data logging?
-4.  The feature logic is a massive `switch`.. no VTable, no function pointer structs, it's quite messy