Update USB.md (#85)

* Update USB.md

added badusb behavior

* Not only sdcard may use to store payloads

For example, you can load it by USB or BT in somewhere in device

Co-authored-by: coreglitch <mail@s3f.ru>

wiki/applications/USB.md

@@ -5,6 +5,10 @@ Firmware mode activating only when chosen from menu.
 
 ## Bad USB mode
 Allow user to run scripts from menu. User should choose script before connecting to victim PC.
+1. User selects payload on filesystem
+2. Press on it with central button, then payload executed, if here a USB connection. Otherwise, it got message "Awaiting connection"
+3. After connection established, it shows progress of execution
+4. At end of execution, it says "ok", user can start script again by pressing central button, or return to list payloads by pressing "back"
 
 ## USB Serial mode
 GPIO can act as UART/I2C/SPI so user can use Flipper as PC serial adapter.
@@ -16,4 +20,4 @@ GPIO can act as UART/I2C/SPI so user can use Flipper as PC serial adapter.
 
 ### Bad USB
 * Payloads
-* Settings
+* Settings