One user, who goes by “MinceR” on a Steam Deck modding forum, documented his autopsy:

# Delete DirectX shader cache for Postal 3 rmdir /s /q "%LOCALAPPDATA%\Postal3\shaders"

: In some cases, reinstalling software or updating to a version that is more efficient with storage can help.

: The programmer can be used to "Repair Health" on chips that have become read-only or are failing due to worn-out memory cells.

: It uses a specific pinout for connection: MOSI connects to the eMMC CMD pin. MISO connects to the DAT0 pin. SCK connects to the SCK pin.