OK, I think the heart of the issue is this error:
blitz.chd NOT FOUND
ERROR: required files are missing, the game cannot be run.
RetroArch [ERROR] :: Failed to load content.
I’ve spot checked a few CHD games and they all seem to behave this way. Maybe it’s time to file a bug?
A larger excerpt of the log, for context:
RetroArch [INFO] :: Using content: /storage/roms/MAME 0.78/blitz.zip.
RetroArch [INFO] :: arg #0: retroarch
RetroArch [INFO] :: arg #1: /storage/roms/MAME 0.78/blitz.zip
RetroArch [INFO] :: arg #2: -s
RetroArch [INFO] :: arg #3: /storage/savefiles
RetroArch [INFO] :: arg #4: -S
RetroArch [INFO] :: arg #5: /storage/savestates
RetroArch [INFO] :: arg #6: -c
RetroArch [INFO] :: arg #7: /storage/.config/retroarch/retroarch.cfg
RetroArch [INFO] :: arg #8: -L
RetroArch [INFO] :: arg #9: /tmp/cores/mame2003_libretro.so
RetroArch [INFO] :: [KMS]: Missed 2 VBlank(s) (Frame: 3428, DRM frame: 23269).
RetroArch [INFO] :: Threaded video stats: Frames pushed: 2285, Frames dropped: 0.
RetroArch [INFO] :: Monitor FPS estimation is disabled for threaded video.
RetroArch [INFO] :: Redirecting save file to "/storage/savefiles/blitz.srm".
RetroArch [INFO] :: Redirecting savestate to "/storage/savestates/blitz.state".
RetroArch [INFO] :: === Build =======================================
Capabilities: MMX MMXEXT SSE1 SSE2 SSE3
Built: Jun 2 2016
RetroArch [INFO] :: Version: 1.3.4
RetroArch [INFO] :: Git: f8b1f05
RetroArch [INFO] :: =================================================
RetroArch [INFO] :: Loading dynamic libretro core from: "/tmp/cores/mame2003_libretro.so"
RetroArch [INFO] :: Overrides: no core-specific overrides found at /storage/.config/retroarch/config/MAME 2003/MAME 2003.cfg
RetroArch [INFO] :: Overrides: no game-specific overrides found at /storage/.config/retroarch/config/MAME 2003/blitz.cfg
RetroArch [INFO] :: Environ SET_VARIABLES.
RetroArch [INFO] :: Remaps: core name: MAME 2003
RetroArch [INFO] :: Remaps: game name: blitz
RetroArch [INFO] :: Remaps: remap directory: /storage/remappings
RetroArch [INFO] :: Remaps: no game-specific remap found at /storage/remappings/MAME 2003/blitz.rmp
RetroArch [INFO] :: Remaps: no core-specific remap found at /storage/remappings/MAME 2003/MAME 2003.rmp
RetroArch [INFO] :: Environ GET_LOG_INTERFACE.
RetroArch [INFO] :: Environ GET_VARIABLE mame2003-frameskip:
RetroArch [INFO] :: 4
RetroArch [INFO] :: Environ GET_VARIABLE mame2003-dcs-speedhack:
RetroArch [INFO] :: enabled
RetroArch [INFO] :: Environ GET_VARIABLE mame2003-skip_disclaimer:
RetroArch [INFO] :: enabled
RetroArch [INFO] :: Environ PERFORMANCE_LEVEL: 10.
RetroArch [INFO] :: Content loading skipped. Implementation will load it on its own.
RetroArch [libretro INFO] :: Found game: blitz [blitz].
RetroArch [INFO] :: Environ SET_ROTATION: 0
RetroArch [libretro INFO] :: osd_fopen (buffer = [/storage/roms/MAME 0.78/blitz/sound102.u95]), (systemDir: [/storage/roms]), (path type dir: [rom]), (path: [1]), (filename: [blitz/sound102.u95])
RetroArch [libretro INFO] :: osd_fopen (buffer = [/storage/roms/MAME 0.78/blitz.zip]), (systemDir: [/storage/roms]), (path type dir: [rom]), (path: [1]), (filename: [blitz.zip])
RetroArch [libretro INFO] :: osd_fopen (buffer = [/storage/roms/MAME 0.78/blitz/blitz1_2.u32]), (systemDir: [/storage/roms]), (path type dir: [rom]), (path: [1]), (filename: [blitz/blitz1_2.u32])
RetroArch [libretro INFO] :: osd_fopen (buffer = [/storage/roms/MAME 0.78/blitz.zip]), (systemDir: [/storage/roms]), (path type dir: [rom]), (path: [1]), (filename: [blitz.zip])
RetroArch [libretro INFO] :: osd_fopen (buffer = [/storage/roms/image/blitz/blitz.chd]), (systemDir: [/storage/roms]), (path type dir: [image]), (path: [2]), (filename: [blitz/blitz.chd])
RetroArch [libretro INFO] :: osd_fopen (buffer = [/storage/roms/image//blitz.chd]), (systemDir: [/storage/roms]), (path type dir: [image]), (path: [2]), (filename: [/blitz.chd])
blitz.chd NOT FOUND
ERROR: required files are missing, the game cannot be run.
RetroArch [ERROR] :: Failed to load content
.