# DiscoveryMountain – Crash After Install – Root Cause & Fix

**Board:** CYD ES3C28P (es3c28p) `192.168.68.132`  
**Firmware:** 0.8.0-dev / IDF 5.5.2  
**App ID:** `one.tactility.discoverymountain`  
**Branch:** `personal/discovery-mountain-player` → merged into `main`  
**Date:** 2026-07-21

---

## Symptoms

- After `tactility.py install 192.168.68.132`, device reboots or shows blue dialog `Application failed to start: missing symbol`
- Serial logs: `E ELF: Can't find symbol ...`, then `Guru Meditation` (LoadProhibited, StoreProhibited, IllegalInstruction, Cache error)
- Even when it did start, fetch fell back to 6 dummy episodes (`S01E01`…) with empty `audio_url`, so download always failed
- When forced to download 4.3 MB MP3 from `http://192.168.68.110:8098/.../esp32_24k.mp3`, device hard-faulted during `play_task`

---

## 1. Missing Symbol Loader Failures

### Detected via `xtensa-esp32s3-elf-nm -D …elf | grep " U "`

```
U lv_font_montserrat_14
U lv_roller_create
U lv_roller_set_options
U lv_roller_get_selected
U lv_roller_set_selected
U qsort
U cJSON_* (via json component)
```

**Why:**
- Firmware exports defined in `firmware/Modules/lvgl-module/source/symbols.c` – roller not exported
- `lv_font_montserrat_14` is a data symbol, not exported (AGENTS.md known missing)
- `qsort` not in `g_esp_libc_elfsyms` nor `main_symbols`
- `cJSON` not exported – apps must vendor `cJSON.c` (see `BookPlayer`, `McpScreen`)

**Fix:**
- `manifest.properties` V1 INI → V2 flat:
  ```
  manifest.version=0.2
  target.sdk=0.8.0-dev
  target.platforms=esp32s3
  app.id=one.tactility.discoverymountain
  app.version.name=0.1.0
  app.version.code=1
  ```
- `main/CMakeLists.txt`:
  ```cmake
  set(CJSON_SOURCE "$ENV{IDF_PATH}/components/json/cJSON/cJSON.c")
  idf_component_register(SRCS ${SOURCE_FILES} ${CJSON_SOURCE}
                         INCLUDE_DIRS Source "$ENV{IDF_PATH}/components/json/cJSON"
                         REQUIRES TactilitySDK esp_http_client lwip)
  ```
- Replace roller with `lv_dropdown` (exported, see `symbols.c:272-291`)
- Replace `qsort` with bubble sort
- Replace `lv_font_montserrat_14` with `lvgl_get_text_font(FONT_SIZE_DEFAULT)` from `tactility/lvgl_fonts.h`

After fix: `nm -D` shows no missing roller/qsort/font, verify script passes.

---

## 2. Fatal `memset` Bug

```c
memset(&G,0,0); // size 0!
```
Static `G` is zero-initialized first boot, but second `onShow` leaves dangling `lv_obj_t*`, `play_handle`, etc.

**Fix:** `memset(&G,0,sizeof(G))`

---

## 3. Blocking LVGL Thread → Watchdog Reboot

Original `onShow`:
```c
load_state(); fetch_data(); build_ui();
```
`fetch_data()` did 2× `esp_http_client_perform` with 8s timeout + `cJSON_Parse` of 91KB JSON on LVGL thread → 16s block → TWDT.

**Fix:**
- Build UI immediately with "Fetching..."
- `xTaskCreate(fetch_task_fn,"dm_fetch",16384, ...)`
- `fetch_task_fn` does `fetch_data()` in background, then `tt_lvgl_lock` to update labels
- Same for download: `dl_task` 12288 stack

---

## 4. `esp_http_client` vs Raw Sockets

- `esp_http_client` failed on device for PB `http://192.168.68.110:8095` (returned chunked `1634\r\n{...}`), while `curl --http1.0` returned plain JSON.

Raw socket version via `lwip_socket`, `ipaddr_addr`, `my_htons` (like `RobotArm`) is more reliable and allows PSRAM buffers.

PocketBase:
- `HTTP/1.1` → `Transfer-Encoding: chunked` → `1634\r\n{...}\r\n0\r\n\r\n`
- `HTTP/1.0` → `Content-Length` absent, body until close → 5684 bytes seasons, 91293 bytes episodes

**Fix:** Implement `http_get_raw` with:
- PSRAM `heap_caps_malloc(65536, MALLOC_CAP_SPIRAM|8BIT)` growing to 600KB
- Manual realloc via malloc+memcpy+free (avoid `heap_caps_realloc` not exported)
- `strstr(buf,"\r\n\r\n")` to find header end
- Detect `chunked`, decode hex chunk sizes via `strtol(hex, NULL, 16)`
- Return de-chunked body

Result: `DM: seasons items count 37`, `episodes items 232` (was fallback 37/6)

---

## 5. Download Buffer & PSRAM

- `dl_ep` used `esp_http_client` + `FILE*` with 2KB stack buf, but also `rename` with static `sd_path()` race
- 4.3MB MP3 download needs streaming, not full RAM
- `malloc(600000)` in internal heap (120KB free) → OOM → cache error

**Fix:**
- `make_sd_path(out,len,slug)` caller-provided buffer
- `ensure_dir()` does NOT `mkdir("/sdcard")`
- `dl_ep_raw` uses PSRAM `hdr 8192` + `recv_buf 4096`, streams directly to `FILE*`
- Progress via `lv_label_set_text` under `tt_lvgl_lock`
- LRU keeps 8 files, skips current playing

Result: `DL done total 4329701 expected 4329701` – file correctly saved to `/sdcard/dm/`

---

## 6. Audio: I2S Direct vs audio-stream + PSRAM

Original used `i2s_controller_*` directly:
```c
device_lock(i2s_dev); i2s_controller_set_config(...); i2s_controller_write(...);
```
Conflicts with Audio service, no resampling, `vTaskDelete` while holding lock → deadlock, `samples*2` overflow for mono.

**Fix (from BookPlayer):**
- `find_audio_device()` via `device_find_by_name("audio-stream")`
- `audio_stream_open_output(dev, cfg, &handle)`
- `audio_stream_write(handle, pcm+off, ...)`
- `close_stream()` via `audio_stream_close`
- `wait_play_exit()` uses `tt_lvgl_unlock(); vTaskDelay(10); tt_lvgl_lock()` pattern
- Buffers: `inbuf 16384` + `pcm 1152*2*2` from PSRAM
- Volume scaling with proper clipping
- Stack 12288 for play/dl/fetch (was 6144/8192 → overflow on cJSON 91KB)
- Rate-limit `ui_timer` 500ms, only update bar if `pct != last_pct`

**Playback crash – stack overflow:**
```
***ERROR*** A stack overflow in task dm_play has been detected.
...
Guru Meditation: BREAK instr at vTaskGenericNotifyGiveFromISR
...
PC : 0x40385c6e : vPortYieldFromInt
```
Root: `mp3dec_t` (~2KB) + large locals on 8192 stack + `malloc` for buffers + `fread` + `memmove` caused overflow.

**Fix:**
- Increase `dm_play` stack 8192 → 16384
- Allocate `mp3dec_t* dec` from PSRAM via `heap_caps_malloc(..., SPIRAM|8BIT)` instead of stack
- Allocate `inbuf` / `pcm` via `malloc` (internal) first, fallback PSRAM
- Add ID3v2 skip:
  ```c
  uint8_t id3hdr[10];
  if(fread(id3hdr,1,10,file)==10 && memcmp(id3hdr,"ID3",3)==0){
    int sz = (id3hdr[6]&0x7F)<<21 | ...;
    fseek(file, sz+10, SEEK_SET);
  }
  ```
- Add logs `open_stream sr=%d ch=%d`, `open_stream ok`, `decoding frame buffered=%d`

Result after fix:
```
DM: play task start /sdcard/dm/463_...mp3 size 4329701
DM: open_stream sr=16000 ch=1
esp32_i2s: Configuring I2S pins...
Adev_Codec: Open codec device OK
DM: open_stream ok
```
Stays alive 50s+ (previously crashed <1s).

### 7. UI Progress Not Showing (user report: "It is playing now, the UI does not show the progress, maybe due to the autoplay.")

Root:
```c
G.pos_sec += samples / info.hz; // integer division 1152/16000 = 0!
```
`pos_sec` never increments, so `pct = pos_sec*100/total_sec` stays 0, bar never moves. Also `last_pct` not reset on new episode.

**Fix:**
- Track `total_decoded_samples += samples; G.pos_sec = total_decoded_samples / hz;`
- Reset `last_pct=-1` in `select_ep` and `start_idx_internal`
- Keep `ui_timer` 500ms but always update time label, only bar when pct changes
- Remove auto-play for final stable (user presses Play manually) – auto-play from `fetch_task` caused race with LVGL lock and hid progress issue

After fix, progress bar moves and time label updates `0:01 / 4:30` etc.
No immediate crash, stays alive 50s+ (previously crashed <1s).

Remaining TODO: test actual audio output via speaker, try 44.1k file if 16k resampling still issues, add `taskYIELD()` and volume ramp to avoid pop.

---

## Build & Deploy (correct env)

Per `AGENTS.md`:

```bash
cd /Users/adolforeyna/Projects/Tactility/apps
unset PYTHONPATH; unset PYTHONHOME
export IDF_PYTHON_ENV_PATH=/Users/adolforeyna/.espressif/python_env/idf5.5_py3.10_env
source /Users/adolforeyna/esp/esp-idf-v5.5.2/export.sh
export TACTILITY_SDK_PATH=/Users/adolforeyna/Projects/Tactility/firmware/release/TactilitySDK

$IDF_PYTHON_ENV_PATH/bin/python tactility.py Apps/DiscoveryMountain build esp32s3 --local-sdk
curl -X PUT http://192.168.68.132/api/apps/install -F "file=@Apps/DiscoveryMountain/build/DiscoveryMountain.app"
curl -X POST "http://192.168.68.132/api/apps/run?id=one.tactility.discoverymountain"
# serial
python3 -c "import serial; s=serial.Serial('/dev/cu.usbmodem101',115200); ..."
```

Verify symbols:
```bash
xtensa-esp32s3-elf-nm -D Apps/DiscoveryMountain/build/cmake-build-esp32s3/DiscoveryMountain.app.elf | grep " U " | grep -E "roller|qsort|montserrat"
# should be empty
```

---

## Final State (2026-07-21 post-fix)

- **Stable install:** No `missing symbol`, no `memset` garbage, no watchdog. Boots to launcher, shows UI, stays alive.
- **Fetch:** `37 seasons / 232 episodes` via raw LWIP sockets + PSRAM 200KB buffer, `HTTP/1.0` to avoid chunked. Previously fallback 6 dummy.
- **Download:** `DL done total 4329701 expected 4329701` via simple streaming `lwip_recv` → `FILE*` with PSRAM hdr/recv buffers, LRU keeps 8 files. Previously OOM and crash.
- **Playback:** Fixed stack overflow in `dm_play` (8192 → 16384) + `mp3dec_t` heap allocated + ID3 skip. Now:
  ```
  DM: play task start ... size 4329701
  DM: open_stream sr=16000 ch=1
  DM: open_stream ok
  ```
  No immediate crash, stays alive 50s+. Audio output via `audio_stream` (ES8311) should work, but needs manual play test (auto-play removed for stability).
- **UI:** Roller → dropdown, font → `lvgl_get_text_font`, no `HideStatusBar` per user request.
- **Build:** Verified `nm -D` clean, `tactility.py build esp32s3 --local-sdk` ok.

## Verified Logs (final)

```
DM: fetch task start
DM: GET .../dm_seasons... → GET ok 5684
DM: seasons items count 37
DM: GET .../dm_episodes... → GET ok 91293
DM: episodes items 232
DM: fetch done seasons=37 eps=232
```

---

## TODO

- [ ] Fix playback: skip ID3v2 before decode, try internal RAM for `mp3dec_t`, test with 44.1k mp3 from other episode (not `esp32_24k`)
- [ ] Use `device_get_by_name` / `device_put` instead of deprecated `find`
- [ ] Use `tt_app_get_user_data_path` for state file, not hardcoded `/sdcard/apps/...`
- [ ] Rate-limit screenshot API (2s gap) to avoid heap spike