The metrics work in PR #10 added a third concurrent TLS client
(metrics → monitoring.googleapis.com) on top of cloud_log → logging
and OTA → ghcr. Three concurrent handshakes pinned ~90 KB of mbedtls
context and pushed `min_free_heap` into the single-digit-KB range,
producing intermittent ESP_ERR_HTTP_CONNECT failures (mbedtls
ALLOC_FAILED at -0x7F00).
Serialize via a shared `Arc<Mutex<()>>` constructed in main and held
**at the call sites** in each sender — std `Mutex` isn't reentrant and
`auth.get_or_refresh()` mints a token (an HTTPS POST to oauth2) that
must run inside the same critical section. Lock granularity:
- cloud_log: token-refresh + entries:write under one lock window.
- metrics: token-refresh + timeSeries.create under one lock window.
- ota::poll_once: token + manifest under lock; release for the
signature bundle fetch's lock; release; verify (CPU, no TLS);
download_and_apply UNLOCKED. Releasing between phases avoids
blocking cloud_log/metrics behind ~2s of pure-Rust X.509/ECDSA work.
- ota::download_and_apply: deliberately not in the lock — multi-second
blob downloads must not block per-5-s log flushes or per-30-s
metrics POSTs.
Plus mbedtls heap knobs that compose with the dynamic-buffer config
already in sdkconfig:
- CONFIG_MBEDTLS_SSL_KEEP_PEER_CERTIFICATE=n: drop the parsed peer
cert chain after handshake. We don't reuse sessions or do mutual
TLS, so we never need it post-handshake. Saves ~3-5 KB per active
session.
Known limitation, deferred to a follow-up: cloud_log/metrics handshakes
can still collide with the held-open OTA download session and OOM the
download mid-stream. The plan there is an `OTA_DOWNLOAD_IN_PROGRESS`
atomic that cloud_log + metrics check before locking — they skip the
POST and let the queue accumulate until the download finishes.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Implements monitoring-plan.md.
- src/gcp_auth.rs: shared TokenProvider. Mints a multi-scope
(logging.write + monitoring.write) JWT once and caches the bearer;
cloud_log + metrics threads share it. Also moves http_post,
parse_signing_key, b64url, now_unix_secs, unix_to_rfc3339,
device_mac out of cloud_log.rs.
- src/cloud_log.rs: cloud_log::run takes Arc<TokenProvider> instead
of owning the JWT/token state. LogQueue::stats() exposes depth +
lifetime drop count for the metrics path.
- src/metrics.rs: periodic snapshot → POST /v3/projects/{id}/timeSeries.
GAUGE INT64 metrics under custom.googleapis.com/esp32/<name>:
free_heap, free_heap_internal, min_free_heap, largest_free_block,
stack_hwm (label task=main|ota|cloud_log|metrics), wifi_rssi,
wifi_channel, cpu_freq_mhz, uptime_secs, nvs_used/free_entries,
cloud_log_queue_depth, cloud_log_dropped_total. Auto-creates
MetricDescriptors on first POST. Cadence via NVS metric_intvl
(gcp namespace), default 300s, 0 disables.
- Each spawned thread publishes its TaskHandle_t into a module-level
AtomicUsize so metrics can read uxTaskGetStackHighWaterMark per
task without holding handles for them. (Xtensa StackType_t is
uint8_t, so the API returns bytes — no word-size multiplication.)
Plus:
- sdkconfig: enable CONFIG_MBEDTLS_DYNAMIC_BUFFER (+ free_config_data,
free_ca_cert) so three concurrent TLS clients (cloud_log + metrics
+ OTA) don't blow our heap budget. Recovers ~15-25 KB per session.
- Makefile: `make flash` and `make run` now pass --partition-table.
Without it, espflash 4.x writes a *default* (factory-only) partition
table over our OTA layout, silently bricking OTA on the device.
- README + provisioning.toml.example: gcloud command for
roles/monitoring.metricWriter; document metrics_interval_secs.
- tools/provision: write metric_intvl NVS u32 (default 300).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Plan for src/metrics.rs — periodic snapshot of heap, stack, wifi, cpu,
uptime, NVS, cloud_log queue stats; POSTed as time series to
monitoring.googleapis.com/v3/timeSeries. Shares the cloud_log SA + key
via a multi-scope JWT and a refactored src/gcp_auth.rs.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
main bumped sha2 0.10 -> 0.11 (PR #8) and switched format!("{:x}", ...)
to hex::encode in src/ota.rs. The auto-merge handled both, plus
Cargo.toml union of dep lists. Cargo.lock had one residual marker around
the firmware deps block (kept main's qualified "sha2 0.11.0" + retained
cloud-logging's rsa/time/tracing-subscriber).
rsa = 0.9 still depends on sha2 = 0.10 internally, so SigningKey<Sha256>
must be parameterised against rsa's re-export (rsa::sha2::Sha256), not
our top-level sha2 0.11.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
- ESP_ERR_NVS_NOT_FOUND from EspNvs::new(gcp,...) is normal for devices
without a [gcp] block; return Ok(None) rather than crashing.
- parse_signing_key trims trailing whitespace; jq -r appends a newline
on top of the PEM's own trailing newline and pem-rfc7468 then errors
trying to parse a second (empty) block.
- Demote per-poll OTA lines (sleeping / no change / manifest) and
per-flush cloud_log lines (posted batch / minted token) from info to
debug. They fire continuously without actionable info, and at INFO
they flood Cloud Logging. INFO stays for OTA update + verify events.
Plus README GCP setup steps and .gitignore for SA key files.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Replaces the stub eprintln sender with the real implementation:
- mint_access_token: builds + signs a service-account JWT (RS256 over
base64url(header).base64url(claims)), POSTs to oauth2.googleapis.com
with the standard grant_type=...jwt-bearer form body, parses the
access_token + expires_in.
- CachedToken: held in the sender thread's local state. Refreshes
300 seconds before expiry (Google issues 1h tokens; we re-mint at
T+55min).
- post_batch: serializes the WriteEntriesRequest with logName,
resource (generic_node + project + MAC node_id), and entries
(severity + jsonPayload + optional timestamp), POSTs to
logging.googleapis.com/v2/entries:write with the bearer.
- Backoff on failure: sleep doubles on each consecutive failure
(capped at 5 min). Batches dropped on POST failure rather than
re-enqueued; loss is surfaced via dropped_before on the next entry.
Crates added: rsa 0.9 (with sha2 feature for AssociatedOid; PKCS#1
v1.5 needs the DigestInfo prefix), time 0.3 (RFC3339 formatting).
main.rs: SNTP startup is now gated on gcp.is_some(). The JWT auth
needs a real wall-clock for / (Google rejects ~5min skew),
so devices with cloud logging pay a one-time ~few-second sync at
boot. Devices without [gcp] skip it. Log entry timestamps themselves
are still optional — when omitted, GCP server-side assigns them.
Cloud Logging severity mapping: tracing TRACE/DEBUG -> DEBUG,
INFO -> INFO, WARN -> WARNING, ERROR -> ERROR (matches GCP's
LogSeverity enum).
device_mac() reads via esp_efuse_mac_get_default and uses the lower
6 bytes as the node_id resource label, so multi-device logs can be
filtered by MAC.
Firmware size: 1.60 MB -> 1.71 MB (+rsa, +time, +sender code).
Still under the 1.94 MB slot.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
First commit of cloud-logging work (logs-plan.md). Foundation only:
the actual NTP/JWT/RSA/HTTPS-POST sender is the next commit; this
sender is a stub that writes 'would POST' to serial.
src/cloud_log.rs:
- GcpConfig::load reads the optional 'gcp' NVS namespace. If any
required key (project_id / sa_email / sa_key_id / sa_key_pem) is
missing, returns Ok(None) — cloud logging is opt-in per device.
- LogQueue: Mutex<VecDeque>-backed bounded ring buffer (256 entries),
drops oldest when full and surfaces the drop count on the next push.
- CloudLogLayer: tracing_subscriber Layer that captures events,
extracts structured fields via field::Visit, applies the configured
min_severity filter, and pushes onto the queue. Uses wall-clock
time when SystemTime::now() is past 2020 (NTP synced); else None
so Cloud Logging assigns server-side timestamps.
main.rs:
- Take NVS first, before any tracing events fire.
- If the gcp NVS namespace is populated, install CloudLogLayer as
the global tracing subscriber and spawn the sender thread (32 KB
stack).
- tracing now uses the 'log-always' feature so events still emit
log records even with a subscriber installed — keeps EspLogger
writing to serial regardless.
tools/provision/:
- Optional [gcp] section in provisioning.toml. Tool emits the gcp
namespace into the NVS CSV when present, validates min_severity
spelling early.
ota.md: gcp namespace added to NVS schema docs.
provisioning.toml.example: commented [gcp] block.
Firmware size: 1.52 MB -> 1.60 MB (tracing-subscriber + cloud_log code).
Plenty of slot headroom remaining (1.94 MB).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Same fix as the publisher in PR #5: sha2 0.11's digest output type
(`Array<u8, _>`) doesn't impl `LowerHex`, so `format!("{:x}",
Sha256::digest(...))` no longer compiles. Switch to `hex::encode`
and add `hex = "0.4"` as a direct dep.
Two call sites in src/ota.rs (manifest digest hash + downloaded layer
hash). esp-idf-svc 0.52 + embedded-svc 0.29 had no API changes that
affected our code paths.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Dependabot fix: drop the root rust-toolchain.toml so Dependabot's
runner doesn't try to use the (uninstalled) `esp` toolchain when
running `cargo update`. The firmware Make recipe now invokes
`cargo +esp build` explicitly so local + CI builds still pin the
right toolchain. Host tools (publisher, provision) keep their own
rust-toolchain.toml = stable.
Dependabot config: batch tools/publisher + tools/provision into one
weekly PR using the `directories:` (plural) field. Firmware Cargo
deps and GHA action versions stay in their own PRs.
ota.md: fold in the provisioning-plan.md content (now that
provisioning is shipped). Updates partition layout numbers, NVS
schema, bootstrap workflow, and trust-config description (no longer
compile-time consts). Adds a 'Soft vs hard trust' section folded
from the plan. Future Work merged.
provisioning-plan.md deleted; README and CLAUDE.md updated to point
at ota.md and drop the dropped file from the project layout.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Implements provisioning-plan.md. The OTA-distributed firmware no longer
contains any secrets or per-device config — those live in NVS and are
written via USB by `make provision` from a (gitignored)
`provisioning.toml`. Same firmware bytes can run on any device.
Firmware changes:
- src/main.rs reads wifi/ssid + wifi/pass from NVS namespace `wifi`.
Strict-inert (sit-and-log) when missing; no compile-time fallback.
WIFI_SSID/WIFI_PASS env! macros gone.
- src/trust.rs becomes a `TrustConfig::load(nvs)` loader. Identities
come from NVS namespace `trust`, key `identities` (JSON-encoded
array). Sigstore root + intermediate PEMs come from `trust/fulcio_root`
and `trust/fulcio_inter` blobs. include_str! gone.
- src/sig.rs and src/ota.rs thread &TrustConfig through verify_bundle
and the OTA loop instead of reading global consts.
- build.rs no longer tracks WIFI_* env changes.
New tool:
- tools/provision/ host-side cargo crate. Reads provisioning.toml,
emits an NVS CSV, shells out to ESP-IDF's nvs_partition_gen.py to
produce a binary NVS image, optionally `espflash write-bin`'s it.
Make targets:
- `make provision` — build NVS image + flash it.
- `make bootstrap` — flash-all + provision (new device setup).
- `make build` no longer requires wifi.env.
- wifi.env removed from prereqs / WIFI_ENV variable removed.
Workflows:
- ci.yml: drops the placeholder wifi.env step, adds a `build provision`
job alongside the firmware + publisher jobs.
- publish.yml: drops WIFI_SSID/WIFI_PASS secret reads. Only secret
needed is the auto-injected GITHUB_TOKEN.
Docs:
- README updated to use `make bootstrap` + `make provision` flow.
Project layout moved to a new repo-local CLAUDE.md.
- provisioning.toml.example committed as the template the user copies.
- wifi.env.example removed (no longer used).
Migration: existing devices need `make bootstrap` over USB. The new
firmware has no embedded creds; OTAing to it without provisioning
would just sit in strict-inert.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
`[profile.release]` now uses lto, codegen-units=1, strip, and
panic=abort (last one matches the build-std=panic_abort already in
.cargo/config.toml). Combined: firmware shrinks from 1.71 MB to
1.52 MB (~9% smaller).
partitions.csv: grow each OTA slot from 1.75 MB to 1.9375 MB by
absorbing the previously-unused 384 KB at the end of flash. Now no
unused space at the end. Repartitioning is a USB-only migration
(`make flash-all`); device migrated locally before pushing.
Net headroom per slot: 126 KB -> 463 KB (3.7x). Plenty for the
upcoming e-ink driver + embedded-graphics stack.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Was structured as a multi-phase plan with each phase marked DONE; now
that the system is operational, restructure as documentation describing
what's built (architecture, components, partition layout, update flow,
anti-bricking + USB recovery, CI signing, on-device verification).
Remaining ideas moved to a 'Future work' section at the end. Dropped
explicit support for legacy cosign .sig formats from the doc.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
CI failure: `embuild ... Could not install esp-idf ... Failed to locate
python ... Too many levels of symbolic links`. Root cause: when
.embuild is restored from a previous workflow's cache, the stale
python-shim/python3 symlink can collide with what `uv python find`
returns -- producing a self-reference that the kernel surfaces as
ELOOP on the next access.
Fix: `rm -f` the shim symlinks before resolving uv's 3.12 path, so
each run starts from a known-empty state.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
sha2 0.11 changed the digest return type from `GenericArray<u8, _>`
to `Array<u8, _>`, which doesn't implement `LowerHex` -- so the
existing `format!("{:x}", Sha256::digest(...))` calls no longer
compile. Switch to `hex::encode` (added as a dep), which works on
any `AsRef<[u8]>`.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Three ecosystems: GitHub Actions (workflow files), firmware Cargo
deps (root), publisher Cargo deps (tools/publisher). Each ecosystem
groups all updates into a single weekly PR.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
CI workflow (.github/workflows/ci.yml):
- Triggers on PRs (and main pushes for redundant fast feedback).
- Two parallel jobs: build the firmware (with placeholder wifi.env),
build the host-side publisher tool. No publishing or signing -- that
remains publish.yml's job.
- Per-PR concurrency: a new push to a branch cancels in-flight CI for
the previous commit on that branch.
GHA action bumps (publish.yml + ci.yml both use the new versions):
- actions/checkout v4 -> v6
- astral-sh/setup-uv v3 -> v8
- esp-rs/xtensa-toolchain v1.5 -> v1.7
- sigstore/cosign-installer v3 -> v4 (defaults to cosign 3, which
still produces the Sigstore Bundle v0.3 format we verify on-device)
- actions/cache v4 -> v5
- Swatinem/rust-cache stays v2 (already current)
Gets us off the deprecated Node.js 20 actions runtime.
Cargo.lock: now tracked. Both crates (firmware and publisher) are
binaries, and binary Cargo.lock should be committed for reproducible
builds. `cargo update` was a no-op except for a couple transitive
patch bumps in the firmware (generic-array 0.14.7 -> 0.14.9).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
GitHub Actions workflow at .github/workflows/publish.yml builds the
firmware on every push to main, pushes it to ghcr.io/imjasonh/esp32,
and cosign-signs it keylessly using the workflow's ambient OIDC token.
Required repo secrets: WIFI_SSID, WIFI_PASS (the GITHUB_TOKEN is
injected automatically).
Trust changes:
- src/trust.rs adds the GHA workflow identity to TRUSTED_IDENTITIES,
alongside the existing email entry. The SAN URI pins the exact
workflow file at refs/heads/main; a malicious commit that adds a
different workflow won't match.
- src/sig.rs's SAN extractor now also handles GeneralName::Uniform-
ResourceIdentifier (workflow URIs), not just Rfc822Name (emails).
Sign-by-digest:
- tools/publisher prints `digest: sha256:...` on stdout (tracing logs
redirected to stderr) so downstream tooling can target the immutable
manifest digest.
- Makefile captures that digest and runs `cosign sign ... $REPO@DIGEST`
instead of `:latest`, eliminating the tag-race window between push
and sign.
Bootstrap: the device's currently-running firmware doesn't know the
GHA identity yet, so the first GHA-signed publish will be rejected.
A manual `make publish` after this lands rolls out the new
TRUSTED_IDENTITIES, after which GHA-signed updates verify cleanly.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Each OTA fetch is now gated on a Sigstore Bundle signature whose Fulcio
cert identifies a member of an allowlist hardcoded in src/trust.rs
(currently imjasonh@gmail.com / accounts.google.com). The allowlist
cannot be changed via OTA -- only by editing source and reflashing
over USB.
Publisher (Makefile): make publish now runs cosign sign --yes after
the publisher push. Cosign keyless OIDC pops a browser the first time;
subsequent signs reuse the cached token within ~10min.
Firmware:
- src/trust.rs: TRUSTED_IDENTITIES list + bundled Sigstore root and
intermediate CA PEMs (trust/fulcio_root.pem, fulcio_intermediate.pem).
- src/sig.rs: parse Sigstore Bundle v0.3 (DSSE envelope), verify (a)
Fulcio cert SAN email + OID 1.3.6.1.4.1.57264.1.1 issuer match the
allowlist, (b) leaf cert chains to bundled Sigstore root via
P-384 ECDSA-SHA384, (c) DSSE signature verifies via P-256 ECDSA-SHA256
over the PAE, (d) in-toto Statement subject digest binds to our
manifest digest.
- src/ota.rs: fetch_manifest now returns the manifest's own SHA256 (the
digest cosign signed), not just the parsed body. New
fetch_signature_bundle walks the OCI 1.1 referrers layout cosign uses
(image index -> inner manifest -> bundle blob). Sig is fetched and
verified before the firmware download starts.
Crates: p256, p384, x509-cert (with pem feature), base64. Adds
~350 KB to the firmware -- repartitioned ota slots from 1.5MB to
1.75MB to fit (USB-only migration). Bumped OTA thread stack to
48KB for cert-parsing headroom.
Verified end-to-end: Jason signed :latest with cosign keyless,
device polled, all four verification steps passed (identity, chain,
DSSE sig, in-toto binding), then downloaded and applied as before.
Phase 4b (Rekor SET / transparency log inclusion proof) and 4c
(operational hardening) remain.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Swap `log = "0.4"` for `tracing = { version = "0.1", features = ["log"] }`.
The `log` feature makes tracing events emit log records when no subscriber
is set, so EspLogger (a log::Logger) keeps writing to ESP-IDF's log system.
No subscriber needed on the device.
Convert call sites in main.rs and src/ota.rs to tracing macros and
restructure the high-signal lines to use structured fields:
ota: boot summary fw="b517946" repo=ghcr.io/imjasonh/esp32 tag=latest
poll_secs=60 last_digest=sha256:c7e09ea...
ota: sleeping sleep_secs=63 failures=0
ota: download progress written=262144 total=1272624
The bridged log records render fields as `key=value` (and `key="value"`
for Debug-formatted ones) appended to the message text -- greppable,
and ready for a real tracing subscriber if we want one later.
Verified end-to-end on the device: phase 3 image OTA'd to the tracing
build, boot summary logged with new field syntax.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
src/ota.rs:
- OtaConfig::load_from_nvs reads `repo` (str), `tag` (str), and
`poll_secs` (u32) from the `ota` namespace, falling back to the
compile-time defaults when keys are absent. Provisioning the values
from outside the firmware is deferred (see ota-plan.md).
- Exponential backoff with +/- 10% jitter on registry errors:
consecutive_failures grows on each failure, sleep is
poll_interval * 2^failures capped at 1h. Jitter is also applied on
the success path so a fleet doesn't poll in lockstep. Randomness
via esp_random().
- Boot summary log: one line on startup with fw version, repo, tag,
poll interval, and last applied digest. Easier to diagnose remote
device state from a single grep.
main.rs passes FW_VERSION (the git SHA from env!) to ota::run, which
includes it in the boot summary. The OtaConfig parameter is gone --
ota::run loads from NVS itself.
ota-plan.md marks phase 3 done (partial); If-None-Match, force-update
GPIO, and an NVS provisioning mechanism explicitly deferred.
Verified end-to-end: published phase 3 image, watched the device pick
it up, boot into ota_1, mark valid, then log the boot summary. Two
consecutive sleeps fired at 64s and 66s for the same 60s base, proving
jitter is firing.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
src/ota.rs polls ghcr.io every 60s on a dedicated 32 KB pthread,
fetches the manifest with an anonymous Bearer token, and on a digest
mismatch streams the layer into the inactive OTA partition while
verifying SHA256 against the descriptor as it goes. Aborts and
bails on size or SHA mismatch; otherwise sets the boot partition,
persists pending_digest to NVS, and reboots.
main.rs detects PENDING_VERIFY on boot and only calls
esp_ota_mark_app_valid_cancel_rollback() after Wi-Fi + the existing
HTTPS bringup checks pass -- so an OTA that breaks networking
auto-reverts on the bootloader's next boot. After mark-valid,
pending_digest is promoted to last_digest in NVS.
GIT_SHA is baked into the firmware via env!() at compile time
(set by the Makefile from `git rev-parse --short HEAD`) and logged
on boot, so we can see which build is running.
Bumped CONFIG_PTHREAD_TASK_STACK_SIZE_DEFAULT to 16 KB; 8 KB
stack-overflowed during HTTPS + JSON + SHA work.
`make monitor` now auto-passes --non-interactive when stdout is
not a TTY, so it works in scripts and background tasks.
Verified end-to-end against ghcr.io/imjasonh/esp32 -- published v1,
flashed via USB, bumped a visible version string, published v2,
and the device polled, downloaded, SHA-verified, rebooted, and
marked the new image valid after bringup. Zero USB intervention.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
tools/publisher/ wraps a firmware .bin as an OCI artifact and pushes
to GHCR using oci-distribution. Mediatypes vnd.esp32.firmware.{v1+json,
bin}; manifest carries org.opencontainers.image.source so GHCR auto-
links the package on first push. Pushes both :latest and :sha-<short>.
A pull-verify subcommand fetches the manifest and layer back and checks
the SHA against a local file -- end-to-end verified pushes and pulls
match bit-for-bit. Same oci-distribution API will be reused for the
device-side fetch in phase 2.
Wired into Make as save-image / publish / pull-verify. GH_TOKEN sourced
from a gitignored gh.env (classic PAT with write:packages -- fine-
grained PATs don't expose a Packages permission for user-owned packages).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2-slot OTA partition table (ota_0/ota_1, 1.5MB each) on 4MB flash.
sdkconfig.defaults is now generated by the Makefile from a template
so we can substitute the absolute path to partitions.csv -- IDF's
CMake resolves CONFIG_PARTITION_TABLE_CUSTOM_FILENAME relative to
embuild's synthetic project under target/, not our repo root.
Adds make flash-all for full erase + bootloader + partition table +
app reflash; doubles as USB recovery if both OTA slots end up bad.
Includes plans for e-ink display work (eink-plan.md) and OCI-based
OTA updates via GHCR (ota-plan.md). Phase 0 of OTA shipped: device
boots into ota_0, verified via esp_ota_get_running_partition() log.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
