Pi 3 simulation had been broken since at least April 2026 (51
fail-events / 24h per docs/PI3_EMULATION_BROKEN.md). Two distinct
defects compounded:
1. qemu_manager.py hard-coded paths for kernel8.img, a device-tree
blob (under a DOS 8.3 short name!), and a 5.4 GiB Raspberry Pi OS
SD image — none of which shipped in the repo or were pulled at
image build.
2. qemu-system-arm + qemu-utils were missing from the Docker image
entirely, so even with the boot files in place QEMU couldn't
launch. Add both to Dockerfile.standalone (~200 MB).
The architecture fix is a new `app.services.boot_images` module:
* Manifest-driven (boot_images/manifest.json, versioned in repo,
declares SHA256 + size for each file, supports an optional
`compressed.{encoding,sha256,size_bytes}` block for assets shipped
as .zst).
* `BootImageProvider` materialises files lazily, atomically (temp +
rename), verifies SHA256 pre- AND post-decompression, caches under
/var/cache/velxio/boot-images, serialises concurrent get() calls
per image set via asyncio.Lock.
* `AssetDownloader` Protocol with two impls:
- `LicenseGatedDownloader` — same flow ESP32 / RISC-V QEMU libs
use (VELXIO_BINARY_BASE_URL + VELXIO_LICENSE_KEY).
- `LocalDirectoryDownloader` — for tests + in-prod use where the
licence-module storage is already on the same filesystem (saves
the loopback HTTP roundtrip on a 1.4 GiB blob).
* `build_downloader_from_env()` picks one — local-dir wins if both
sets of env vars are present, so the prod box short-circuits to
direct disk reads automatically.
* Lifespan hook in qemu_manager.py pre-warms the cache on container
boot so first-time user requests don't pay the 30-60 s download
+ decompress latency.
Adding a future board kind (Pi 4 / Pi 5) is now: upload assets via
upload-binary.sh, append an entry to manifest.json, register a
lifespan pre-warm in the new board's service module. Zero edits to
provider.py / downloader.py.
Manifest entries for raspberry-pi-3:
kernel8.img 9 695 883 bytes (uncompressed)
bcm2710-rpi-3-b.dtb 34 687 bytes (uncompressed)
raspios-trixie-armhf.img 5 729 419 264 bytes raw
/ 1 488 002 803 bytes .zst on wire (zstd -19)
source: 2026-04-21 build from raspberrypi.com
Tests: 21 new unit tests covering manifest parsing, integrity
helpers, both downloaders, and the provider's idempotent /
concurrent / integrity / decompression / warmup paths. In-process
FakeDownloader keeps the suite under 1 s and httpx-free.
Docs: new docs/BOOT_IMAGES.md describes the architecture, on-disk
layout, named-volume operation, and the procedure for adding a new
image set.
After Phase 4 of the OSS / pro split, the OSS code base imports zero
auth/DB modules (verified with grep across backend/app/). But the
requirements.txt + config.py + .env.example + docs still listed
SQLAlchemy, aiosqlite, JWT/bcrypt, OAuth, SECRET_KEY etc. as if they
were live. Self-hosters running `pip install -r requirements.txt`
were pulling ~30 MB of packages the code never imports.
Changes:
* backend/requirements.txt — drop sqlalchemy, greenlet, aiosqlite,
python-jose, passlib[bcrypt], bcrypt, authlib, email-validator,
python-multipart. Keep fastapi, uvicorn, websockets, pydantic,
pydantic-settings, httpx, mcp, esptool, wasmtime — everything OSS
actually uses.
* backend/app/core/config.py — Settings reduced to FRONTEND_URL only.
Comment explains the overlay path that adds the rest at Docker
build time.
* backend/.env.example — same trim: only FRONTEND_URL, with a comment
explaining why this file is almost empty.
* README.md — "Auth & Project Persistence" section rewritten to
describe .vlx export/import. Env-var table reduced to a single row.
Stack table updated: no SQLAlchemy, no JWT, persistence = .vlx
files.
* CLAUDE.md — intro line updated (Auth: None, persistence: .vlx).
Key-file-locations rewritten to list the OSS-stateless backend +
the new lib/proRoutes / proSession / proSaveAction seams, with an
explicit "removed in the split" note pointing to velxio-prod.
Stores section drops useAuthStore (overlay-only now). Backend
gotchas drop the bcrypt + email-validator + model-import notes.
Implemented-features list replaces "Auth + URL persistence + user
profile" with portable .vlx export/import.
* docs/ESP32_EMULATION.md — two `docker run` examples dropped the
`-e SECRET_KEY=...` arg (no longer needed).
OSS build verified end-to-end (285 SEO pages prerender, 20 stateless
routes, zero sqlalchemy imports).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Resolves several install pain points reported by users (#108, #120) and
removes the obligatory upstream-clone step that confused contributors and
slowed down every Docker build.
Install fixes:
- nginx: server_name → catch-all default_server, drop Debian's stock site
so reverse-proxied users no longer get the "Welcome to nginx" page.
- entrypoint: auto-generate SECRET_KEY at first boot, persisted under
data/.secret_key. backend/.env is now optional in docker-compose.yml.
- backend: add greenlet>=3.0.0 (SQLAlchemy async dep that was missing on
some Python builds — caused uvicorn startup failures on WSL).
Wokwi libs come from npm:
- @wokwi/elements 1.9.2, avr8js 0.21.0, rp2040js 1.3.2 are pinned in
frontend/package.json. Vite aliases removed.
- Dockerfile.standalone no longer clones avr8js / rp2040js / wokwi-elements
/ wokwi-boards. Frontend stage is just COPY + npm install + build:docker.
- Board SVGs vendored under frontend/public/boards/ (10 deduped against
existing files, 2 truly new). third-party/wokwi-* clones become reference-
only credits — generate-component-metadata.ts skips gracefully when absent.
Production config split out:
- docker-compose.prod.yml, deploy/nginx.prod.conf, nginx-host-velxio*.conf,
update-third-party.bat removed. Production deployment lives in its own
repo: https://github.com/velxio/velxio-prod (host nginx + HTTPS + backups
+ pinned upstream commit).
Verified locally: 1161 frontend tests pass, build:docker completes clean.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
- Implemented `esp32_spi_chip_demo.ino` to demonstrate SPI communication with a 74HC595 shift register.
- Created `esp32_uart_chip_demo.ino` for UART loopback testing with ROT13 transformation.
- Added Python tests for compiling chips and sketches, ensuring valid WASM output and successful compilation for various board families.
- Developed end-to-end tests for ESP32 with custom chips using I2C and SPI, validating synchronous communication through the backend.
- Introduced GPIO bridge tests to verify serial communication and GPIO state changes.
- Ensured all tests validate the expected behavior of the custom chips and their interaction with the ESP32 firmware.
- Added detailed logging for GPIO changes, system events, and errors in simulation websocket.
- Improved ESP32 firmware handling by merging individual binaries into a single 4MB flash image.
- Updated ESP32 bridge to handle serial output and GPIO changes with appropriate logging.
- Introduced integration test for ESP32 emulation, covering compilation, WebSocket connection, and event handling.
- Enhanced examples to include ESP32 projects and updated the examples gallery to reflect new board types.
- Refactored simulator store to manage ESP32 bridge and simulator instances more effectively.
- Updated requirements to include esptool for ESP32 firmware management.
- Add LoginPage and RegisterPage for user authentication.
- Create UserProfilePage to display user projects.
- Implement ProjectPage for viewing and editing individual projects.
- Introduce authService for handling user login, registration, and session management.
- Add projectService for managing project data retrieval and manipulation.
- Enhance EditorPage with file management capabilities and save prompts.
- Introduce Zustand stores for managing authentication, editor state, and project state.
- Add reserved usernames utility to prevent certain usernames during registration.
- Update compilation service to handle multiple files for Arduino sketches.
- Added SimulatorCanvas component for rendering the simulator interface.
- Integrated Wokwi components (Arduino, LED, Resistor, Pushbutton, Potentiometer) into the simulator.
- Created PinManager to handle pin state changes and notifications.
- Developed AVRSimulator class for emulating Arduino Uno functionality.
- Implemented hex file loading and compilation service.
- Added CSS styles for the simulator interface.
- Established Zustand stores for managing editor and simulator states.
- Created utility functions for parsing Intel HEX format.
- Set up Vite configuration for the frontend project.
- Added batch scripts for starting backend and frontend servers, and updating Wokwi libraries.