Constant PARKING_TAIL 

pub const PARKING_TAIL: [u8; 16];

One ADPCM block of silence that loops onto itself, written after every uploaded sample so a voice running past its own END lands on nothing.

Shift/filter 0, flags 0x07 = LOOP-START | REPEAT | END, then fourteen bytes of zero nibbles. LOOP-START is the bit that matters: the hardware latches the repeat address off this block while decoding it, which does not depend on anything written before key-on. Self-looping silent ADPCM block appended after each packed one-shot.

Cookers that build a bank for later bulk upload should append this after every sample. This gives silicon the same loop-start marker as Bank without duplicating the hardware-specific byte sequence outside the SDK.