CBHD Firmware, Cross-Flashing and Drive Compatibility

What nobody has documented

No research pass found a documented, successful firmware cross-flash in either direction-HD DVD → CBHD or CBHD → HD DVD-or any region/DRM hack, ripping report, directory dump or MediaInfo log from a CBHD disc. No public consumer firmware updates or hacks were released to cross-convert between HD DVD and CBHD. What exists is speculation from 2008-2009 and three different technical arguments that only partly agree.

Contemporary speculation (2008-2009)

  • AVSForum thread “Latest news – China turns HDDVD into CBHD” (2008): early debate over whether HD DVD drive firmware could handle CBHD modulation. Richard Paul argued HD DVD players are physically incapable.
  • See You Next Wednesday blog (28 May 2009): Western hopes for an HD DVD → CBHD firmware hack.
  • Gizmodo (2008): CH-DVD player essentially an HD DVD player “whose laser is set at a different modulation”; manufacturing could share processors and optical pickups.
  • AVSForum master thread: an HD-XA2 owner promised to test HD DVD discs in a CBHD player in a store; no follow-up result found.
  • What Hi-Fi forum (16 Oct 2009): confirms CBHD discs will not play in HD DVD players because of AVS/DRA and new copy protection.

Argument 1 – modulation and channel hardware

A firmware change could potentially alter codec support, navigation, DRM, file-system interpretation and software decoding. It cannot make a pickup/servo/channel decoder support a different modulation system unless the signal-processing hardware already supports that mode. The Novatek NT90912 explicitly lists FSM alongside ETM/EFM/EFM+. Patents CN201549222U and CN102682801B show optical systems engineered around CBHD’s specific requirements, including BD vs CBHD NA differences.

Scenario Assessment
Ordinary Toshiba/Onkyo/Microsoft HD DVD player → CBHD by firmware No evidence of successful conversion
HD DVD firmware conversion in general Potentially possible only on hardware already containing CBHD channel support
Later Chinese universal optical drive (Novatek FSM-capable) Much more plausible because chips existed that supported CBHD

Argument 2 – SoC decoders and firmware structure

Another pass treats late HD DVD and CBHD optical pickups as functionally interchangeable (405 nm diode, same focal lengths, tracking servos and RF stages for 0.6 mm substrates) but calls cross-flashing an HD DVD player into a CBHD player architecturally impossible at the SoC level:

  • Hardware ASIC decoders: Toshiba HD DVD players used Broadcom (e.g. BCM7411) or NEC SoCs with hard-wired logic for MPEG-2, VC-1 and H.264 video and Dolby Digital, DTS and E-AC3 audio; they had no programmable microcode capable of AVS or DRA decoding.
  • Firmware structure: A CBHD disc in an HD DVD player mounts only as a raw ISO/data disc; the player cannot find HVDVD_TS execution scripts or AACS certificates and reports unrecognised media.
  • Bricking risk: Flashing a Toshiba HD DVD player’s EEPROM with a dumped Shinco or TCL firmware binary will permanently brick it-memory maps, GPIO, display drivers and front-panel microcontrollers share no register alignment across manufacturers.

Source tension: the claim that a CBHD disc mounts as a data disc in an HD DVD player, and the claim that HD DVD PC drives read CBHD sectors, conflict with the modulation argument and with findings that HD DVD players cannot read CBHD because of FSM. Also, the TCL THBD-1008 is built on a Toshiba HD-A30 board with an NEC EMMA3 SoC, which softens a pure “no shared hardware” story for at least one commercial CBHD model.

Argument 3 – shared Toshiba platform

Because the THBD-1008 reuses a Toshiba HD-A30 motherboard with changed firmware and power supply, a theoretical route exists: changing modulation/demodulation in the front-end channel IC or firmware, plus the navigation layer, might make an HD DVD drive read CBHD. Nobody has shown this. Drive firmware would still have to handle FSM 4-6 instead of ETM 8-12. Shinco’s CBHD-9100 is only “likely” HD-A35-derived in forum discussion, not confirmed by a service manual dump.

Firmware archive leads

No CBHD firmware files, update discs (升级光盘/固件) or dumps were found. Explicit dump target: TCL THBD-1008 Spansion S29GL256N 32 MB NOR flash. Recommended dump motivation: CETC parser, file-system parser, codec libraries, DRM implementation, hardware register definitions and strings naming internal file structures.

HD DVD firmware resources useful for comparison (not CBHD): hddvd-revived firmware catalogue; hd-dvd.org firmware page; Internet Archive “HD-DVD Firmware Update Archive: Toshiba”; AVForums European Toshiba firmware threads; Reddit r/HDDVD “HD DVD Emulator Firmware.” Generic cross-flashing material (LG/Renesas tutorials, MakeMKV UHD drive flashing, DVDFab, LTO autoloader guides) teaches technique without supplying CBHD binaries.

Optical compatibility is not firmware compatibility

Patent CN102682801B (Hong Kong Polytechnic University, priority 17 March 2011) describes a freeform objective lens focusing 405 nm for both BD (NA 0.85) and CBHD (NA 0.65). Patent CN201549222U discusses pickups that must handle incompatible CBHD and Blu-ray geometries. These documents show optical engineers treated format coexistence as a lens and pickup problem. Firmware alone does not invent NA 0.65 behaviour on an NA 0.85 head, and does not invent FSM demodulation on an ETM-only channel ASIC.

Donor strategy for repair therefore separates layers: Toshiba HD-A30/A35 family parts may supply PSUs, loaders and possibly boards for THBD-1008 / CBHD-9100 lineage machines; pickups should be matched by photographing labels on a real CBHD unit before buying; firmware should not be expected to cross-flash. PHR-803T-family HD DVD pickups are plausible candidates only after label comparison.

Working conclusions

  1. No successful consumer cross-flash is on record.
  2. FSM channel support is the hard gate for reading pressed CBHD.
  3. AVS/DRA ASIC absence blocks many HD DVD SoCs even if sectors somehow appeared.
  4. THBD-1008’s Toshiba motherboard makes it the most interesting firmware-comparison target, not a proven flash candidate.
  5. Novatek FSM-capable front ends are the more plausible base for any future universal drive work.
  6. Dumping CBHD firmware is higher value than hunting mythical HD DVD→CBHD update discs.

Forum hopes from 2009 assumed China had merely re-skinned HD DVD. The engineering record-FSM, CETC, DKAA/AACS split, AVS/DRA-says otherwise. Cross-flashing remains a research question with negative empirical results so far, not a weekend project with a USB-TTL cable.

How the three arguments interact

Argument 1 (modulation hardware) blocks any plan that treats firmware as omnipotent: without FSM in the servo/channel ASIC, a flashed EEPROM cannot invent a demodulator. Argument 2 (SoC codecs) blocks plans that assume AVS/DRA can run on Broadcom/NEC HD DVD silicon that only hard-wires MPEG-2/VC-1/H.264 and Dolby/DTS/E-AC3. Argument 3 (shared Toshiba platform) keeps a narrow door open for the THBD-1008 specifically, because that machine already pairs a Toshiba-derived board with CBHD firmware-but the door opens onto front-end channel work, not a consumer update disc.

Pickups may be the least of the problems if Gemini’s interchangeability claim holds for late 0.6 mm blue-laser heads. Even then, channel coding and navigation diverge. Patents CN201549222U and CN102682801B further show that CBHD versus Blu-ray optics needed deliberate lens and pickup engineering; they do not license wishful HD DVD→CBHD flashes.

What a responsible dump campaign looks like

  1. Acquire a working TCL THBD-1008 and photograph the Spansion package before desoldering or clip-reading.
  2. Acquire a Shinco CBHD-9100 for comparison strings and loader behaviour.
  3. Store raw dumps hashed; do not redistribute decrypted movie keys if present.
  4. String-search for CETC, CBHD_TS, HVDVD_TS, DKAA, AVS, DRA, FSM and UDF identifiers.
  5. Diff against public Toshiba HD-A30 firmware only as a map, never as a write source.
  6. Document Novatek or other front-end part numbers from board photos before scavenging donors.

No pass found 升级光盘, vendor update download pages or Taobao firmware sellers for CBHD models. Generic LG/Renesas or MakeMKV UHD flashing tutorials teach electrical practice only. The archival outcome to seek is understanding-parsers, register maps, file-structure names-not a mythical “enable CBHD” checkbox on a Western HD DVD player.

Store-test anecdotes remain incomplete: an HD-XA2 owner promised to try HD DVD discs in a CBHD deck and never reported back; What Hi-Fi readers were told CBHD discs would not play in HD DVD players because of codecs and copy protection. Those fragments align with commercial incompatibility even where hardware DNA is shared.

Even shared Toshiba DNA on the THBD-1008 does not license casual EEPROM swaps. Memory maps, GPIO wiring, display controllers and front-panel microcontrollers differ enough across manufacturers that flashing Shinco binaries onto Toshiba-derived boards-or the reverse-is described as a permanent brick risk. Read-only dumps remain the productive path; write experiments belong last, after string analysis and channel chip identification.

Further reading on historic video formats

If you want to learn more about historic video formats, get The History of Physical Video Formats from the Frontier by Stephen Driver on Amazon: