Flash agent roadmap: SPI flash, high-speed UART, defib integration

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Flash Agent Feature Roadmap

Done

PR #10 — Bare-metal agent with COBS protocol

• ARM32 bare-metal agent, self-update, disconnect survival

PR #12 — Agent CLI

• defib agent upload/info/read/write commands

PR #13 — High-speed UART

• CMD_SET_BAUD up to 921600 with triple fallback

PR #14 — SPI flash read

• FMC init, JEDEC ID, memory-mapped flash reads, 16MB dump verified

PR #15 — Flash dump reliability

• sf probe fix, sanity check, transport retry + resume

PR #19 — Flash erase + write

• CMD_ERASE, CMD_WRITE to flash, sector unlock, FMC mode switching

PR #20 — MMU/D-cache + COBS fix

• ARMv7 MMU with D-cache
• Critical: COBS decode trailing zero strip bug (root cause of all write failures)
• Fixed _recv_packet_sync partial frame stashing

PR #34 — Flash program pipeline + reboot

• CMD_FLASH_PROGRAM: RAM → erase + program locally
• Sysctrl reboot (0x12020004 = 0xdeadbeef)
• End-to-end: agent → flash OpenIPC → reboot → login prompt

PR #35 — Streaming write

• Removed per-packet backpressure (no longer needed with COBS fix + D-cache)
• 3x faster: 30 → 77 KB/s

PR #36 — Windowed ACK

• Send W=16 blocks (256KB) back-to-back, read ACKs after
• 88 KB/s write — 96% of line speed at 921600 baud

PR #37 — CMD_FLASH_STREAM + FMC read fix

• CMD_FLASH_STREAM (0x0B): streaming flash write with double-buffer pipeline
• Receive into buffer A while erasing+programming buffer B — 189s at 87 KB/s for 16MB
• 72KB soft_rx FIFO + UART drain during flash ops for reliable buffering
• Fix: FMC boot mode memory window wraps at 1MB — switched to register-based SPI READ
• Verified: 16MB random data → write → power cycle → CRC32 readback: byte-perfect

PR #38 — Skip 0xFF sectors and pages

• 32-byte sector bitmap in CMD_FLASH_STREAM payload — host marks all-0xFF sectors
• Agent erases 0xFF sectors but skips data transfer + page programming
• Page-level 0xFF detection: skip programming all-0xFF pages within data sectors
• 41% faster for typical firmware: 112s vs 189s (148/256 sectors skipped for 8MB OpenIPC in 16MB image)

Performance Summary

Operation	Speed	16MB Time
Flash READ (921600)	87 KB/s	3.1 min
Flash STREAM (double-buffer)	87 KB/s	3.1 min
Flash STREAM (0xFF skip, 8MB fw)	150 KB/s	112s
Flash erase + program (hidden)	—	overlapped
Boot protocol upload	9.6 KB/s	24.5s / 230KB
Full recovery (dead → OpenIPC login)	—	~3 min

Remaining

Defib app integration

• Wire agent flash pipeline into TUI (upload → flash → reboot) (PR Add defib agent flash one-command firmware install #41)
• defib agent flash one-command firmware install (PR Add defib agent flash one-command firmware install #41)
• WebUI: agent flash via WebSerial
• Package pre-compiled agent binaries in wheel/sdist

Multi-SoC testing

• hi3516ev200 / gk7205v200 (same V4 generation)
• hi3516cv300 (V3, UART 0x12100000)
• hi3516cv610 (V5, UART 0x11040000)

Protocol enhancements

• Windowed ACK for higher write throughput (PR Windowed ACK: 88 KB/s write (96% line efficiency) #36)
• Streaming flash write (upload + program in parallel) (PR Add CMD_FLASH_STREAM with double-buffer pipeline and fix FMC read bug #37)
• FMC memory window stale reads (PR Add CMD_FLASH_STREAM with double-buffer pipeline and fix FMC read bug #37 — was 1MB boot mode limit, fixed with register reads)
• 0xFF sector/page skip (PR Skip 0xFF sectors and pages in CMD_FLASH_STREAM #38)
• Agent version/capabilities in INFO response (PR Add agent version and capabilities to INFO response #40)