Removed I2CS bmSTOP "bus reset" from bcm4500_boot() and debug modes.
Sending STOP with no active transaction puts the FX2 I2C controller
into an inconsistent state where subsequent START+ACK detection fails.
Root cause identified through incremental debug modes (wValue 0x80-0x85)
on live hardware: mode 0x82 (with bmSTOP) fails, mode 0x85 (identical
but without bmSTOP) succeeds. Raw I2C reads confirm BCM4500 is alive
the entire time -- only the controller state is corrupted.
BCM4500 now boots successfully in ~90ms. Three I2C devices found on
bus: 0x08 (BCM4500), 0x10 (tuner/LNB), 0x51 (EEPROM).
Also in this commit:
- Timeout-protected I2C functions replacing fx2lib bare while loops
- I2C bus scan and debug mode infrastructure
- Kernel driver blacklist for dvb_usb_gp8psk
- Test tools for incremental boot debugging
- Technical findings documented in docs/boot-debug-findings.md
Custom firmware (SDCC + fx2lib) implements all stock vendor commands
(0x80-0x94) plus new commands for spectrum sweep (0xB0), raw BCM4500
register access (0xB1/0xB2), and blind scan (0xB3). Compiles to 6.3KB
of code with healthy RAM margins.
RAM loader (fw_load.py) uses the FX2 0xA0 vendor request to load
firmware into RAM without touching EEPROM -- power cycle restores
factory firmware. Supports Intel HEX and raw binary formats.
New tools:
- tools/eeprom_write.py: EEPROM firmware flash with backup, verify, dry-run
- tools/ts_analyze.py: MPEG-2 transport stream analyzer with PAT/PMT parsing
DVB-S2 investigation confirms BCM4500 hardware limitation (no LDPC/BCH silicon).
Fix --json flag on tune.py subcommands (argparse parent/child scoping).
All tools verified against live SkyWalker-1 hardware.
Python tool (tools/tune.py) implements all vendor USB control
commands for tuning, LNB control, DiSEqC switching, and MPEG-2
transport stream capture via pyusb. Includes CLI subcommands for
status, tune, stream, diseqc, and lnb operations.
Consolidated hardware reference merges all Phase 1 analysis into
a single 12-section document covering the complete USB interface,
all 30 vendor commands, BCM4500 demodulator protocol, GPIF
streaming path, DiSEqC timing, and cross-version firmware
comparison.
Updater EXEs are packed (RWX sections, near-random entropy) with anti-debug
protection (IsDebuggerPresent/SoftICE check). Bypassed by running under plain
Wine and reading /proc/PID/mem with elevated privileges.
SW1 v2.13.x updater contains 3 firmware variants (likely .1/.2/.3):
- All use LJMP 0x170D entry, 9322-9377 bytes, 10 C2 records each
- FW2 vs FW3 differ by 1525 bytes (most similar pair)
Rev.2 v2.10.4 updater contains 1 firmware image:
- PID=0x0202 (vs SW1's 0x0203), LJMP 0x155F, 8843 bytes, 9 C2 records
All images use standard Cypress C2 EEPROM format with entry at 0xE600 (CPUCS).
Previous RAM dumps via 0xA0 vendor request turned out to be live FIFO
data, not firmware - the Genpix FX2 firmware overrides the standard
0xA0 handler. Discovered that I2C_READ (0x84) with wValue=0x51 and
wIndex=offset reads the boot EEPROM directly.
EEPROM contents (Cypress C2 format):
- VID:PID 09C0:0203, config 0x40 (400kHz I2C)
- 9,472 bytes of 8051 firmware in 10 load records
- Code range 0x0000-0x24FF, entry at LJMP 0x188D
- Ghidra auto-analysis finds 61 functions
Tools: eeprom_dump.py (full dump), eeprom_probe.py (I2C protocol discovery)
Dumped 8KB internal RAM and 64KB external RAM from SkyWalker-1
serial #00857 via Cypress FX2 vendor request 0xA0. Device reports
FW v2.06.4 (build 2007-07-13). Tool also scans all vendor USB
commands and probes device status registers.
