bcsfe-save-roundtrip

BCSFE Save Round-Trip (Battle Cats EN, rooted BlueStacks)

Edit the live Battle Cats EN save end to end: pull byte-exact, edit headlessly, push in place so uid + SELinux context survive. The non-obvious parts (RAM flush, in-place cat >, MSYS path mangling) are what bite.

Environment

• Package jp.co.ponos.battlecatsen; save at /data/data/<pkg>/files/SAVE_DATA (~539 KB primary). Siblings: SAVE_DATA.OLD = BC's own rollback, BACKUP_SAVE_DATA = cloud/transfer, SAVE_DATA4 = secondary slot.
• adb = C:\ADB\adb.exe, device 127.0.0.1:5555. App uid u0_a65 = numeric 10065. BCSFE-Python 3.3.0 venv: D:\ReverseTools\Android\BCSFE-Python\.venv.
• Serial changes across BlueStacks restarts (emulator-5554 vs 127.0.0.1:5555) — adb devices first, then target -s <serial>.

PULL (byte-exact, no CRLF/MSYS mangling)

Do it in PowerShell, not git-bash (MSYS rewrites /data & /sdcard args). BC holds the save in RAM, so flush first:

& C:\ADB\adb.exe shell input keyevent KEYCODE_HOME   # backgrounding flushes to disk
Start-Sleep -Seconds 3                                # mtime should now ~= device clock
& C:\ADB\adb.exe shell "su -c 'cp /data/data/jp.co.ponos.battlecatsen/files/SAVE_DATA /sdcard/SAVE_DATA && chmod 666 /sdcard/SAVE_DATA'"
& C:\ADB\adb.exe pull /sdcard/SAVE_DATA D:\WSA\saves\SAVE_DATA

(Force-stop does not flush — only backgrounding does. Confirm freshness by mtime ≈ device clock.)

EDIT headlessly (no interactive menu)

from bcsfe import core
sf = core.SaveFile(core.Path(p).read())   # cc auto-detected as 'en'
# ... mutate parsed objects (sf.catfood, sf.ototo.cannons, ...) ...
sf.to_file(core.Path(out))                # re-serializes via to_data(), incl. checksum

For a human, open the editor with bcsfe -i <path> (-i/--input-path skips the load prompt).

PUSH safely (the non-obvious part)

1. am force-stop <pkg> FIRST — else BC's autosave overwrites you.
2. Back up on device: cp SAVE_DATA SAVE_DATA.before-<ts>.
3. adb push to /sdcard, then overwrite in place with cat >:

su -c 'cat /sdcard/new_save > /data/data/jp.co.ponos.battlecatsen/files/SAVE_DATA; \
       chown 10065:10065 /data/data/jp.co.ponos.battlecatsen/files/SAVE_DATA; \
       chmod 660 /data/data/jp.co.ponos.battlecatsen/files/SAVE_DATA; \
       restorecon /data/data/jp.co.ponos.battlecatsen/files/SAVE_DATA'

The cat > reuses the existing inode, so owner + SELinux app_data_file context survive. A fresh cp/push as root lands root:root with the wrong context and BC rejects/resets the save. Then verify md5sum device == local. User reopens BC to load it.

MSYS PUSH GOTCHA (cost an empty-file wipe — also applies to event_0 pushes)

In git-bash, adb push <src> /sdcard/<dst> silently mangles the destination via MSYS path-conversion (/sdcard/... → C:/Program Files/Git/sdcard/...) so the push fails — and the in-place step cat /sdcard/<dst> > <devfile> opens <devfile> for write, truncating it to 0 bytes BEFORE cat runs, leaving the device file EMPTY (md5 d41d8cd98f00b204e9800998ecf8427e).

Fix: export MSYS_NO_PATHCONV=1 before any git-bash adb push/shell with /sdcard or /data args (or just do the push in PowerShell). Always md5sum the device file after the write — that is what catches the empty/wrong-content state.

Ototo cannon unlock (the "no equip button" fix)

sf.ototo.cannons = {cannon_id: Cannon(development, levels)} plus selected_parts (a [foundation, style, effect] triple per formation slot = the equip state). cannon_id 0 = basic; 1–7 = Slow Beam / Iron Wall / Thunderbolt / Waterblast / Holy / Breaker / Curse-blast. development: 0 none / 1 foundation / 2 style / 3 effect(full).

The in-game Change/customize button only appears once lines are developed past default — set development=3 and levels >= 1 (effects need level ≥ 1; merely building gives no effect). Editing the save does not auto-equip — the player still picks the Foundation/Style/Effect mix in the Ototo screen (Gamatoto → swipe left); it binds per formation slot.

Live-game care: read-only discovery is safe; prefer reversible save-edits over forcing unverified in-memory fields. On a "broken" state, kill all hooks + restart BC first, then restore the SAVE_DATA.before-* backup.