YACP (Yet Another CrossPoint) is a personal, opinionated firmware for Xteink X3 and X4, derived from CrossInk and CrossPoint. It keeps the reader focused: reopen the current book quickly, turn pages responsively, and avoid background work that does not improve reading.

Its main direction is lower energy use and predictable performance on an ESP32-C3 without PSRAM. Quick Resume, reduced idle, USB, display, and SD-card work, debounced progress writes, on-demand loading of secondary data, and bounded rendering buffers keep the normal reading path quiet and efficient.

A lightweight one-book Home, Lexend Deca and Bitter fonts, Reading Rhythm, reading statistics, and autonomy tracking remain available. X3 is the primary optimisation target; X4 builds are also provided.