diskOS Disco! 2.5.1

A performance and stability update, with optional Library letter-wheel navigation and clearer track popups.

Library letter wheel

Choose Settings > Playback > Library seeking > Letter wheel. The existing A-Z picker remains the default.

• Hold the current-letter marker on the scrollbar (or tap it) to open the wheel.
• Move clockwise to advance through letters; reverse to go back.
• Tap the large centre letter to jump immediately, or release and wait one second to confirm.
• Touching again suspends the deadline; Back cancels.
• The overlay background is 50% opaque. Null uses square controls; other themes use circles. The centre letter uses your Music title font.

Fixes and responsiveness

• Squash volume accepts player updates promptly outside a drag or pending adjustment. Retries run only after a failed send, and the smaller entrance/exit respects disabled animations. Disco and Null volume handling is unchanged.
• Squash Library jump-to-track highlighting clears when manual browsing starts.
• Album Wall prepares covers in a bounded background worker, rejects stale results, pauses hidden polling and trims unused cover buffers after a quiet period.
• Background artwork prewarming waits for UI idle. Database reads use separate nonblocking connections while preserving reads inside the UI's own write transactions.
• Secondary favourites/history storage and cold immersive image buffers allocate when needed rather than remaining permanently resident.
• Long track-popup titles and artists keep scrolling in Disco, Null and Squash; Squash text stays farther inside the round edge. Music screen scrolling preferences remain unchanged.

Album Roulette

The final screen has Again and Exit pills beneath Play. Again rerolls the prepared album pool without decoding its covers again. Exit returns to Music. App colours and typography follow the active theme; Play retains its white/black appearance. Reopening no longer waits on an unfinished loader in the UI thread.

The wheel image is stored losslessly compressed. The executable is 5,730,516 bytes, about 7.4% smaller than fixed public 2.5.0 main. No fonts, artwork formats or features were removed.

Diagnostics

The boot log identifies 2.5.1. Successful volume-send spam is debug-only; errors and unusually slow UI frames remain rate-limited diagnostics. Logs receive periodic size checks with one bounded previous .1 copy. The main log targets 256 KiB and auxiliary logs 64 KiB each; checks run every 30 seconds rather than enforcing a strict byte quota.

Install and validation

Use the standard diskOS Disco update process and your existing signing key. A raw mq_ui is an interface payload, not a signed firmware update. See Updating.

Native LVGL interaction tests, SQLite lock/contention tests, artwork/cache and queue tests, log rotation checks, exact wheel-pixel comparison and the static MIPS build passed. No new physical-device FPS, battery-life or long-run memory claim is made. See detailed validation.