emulator: Linkboy type: standalone core_classification: embedded_hle source: "https://play.google.com/store/apps/details?id=com.pixelrespawn.linkboy" upstream: closed-source version_source: url: "https://play.google.com/store/apps/details?id=com.pixelrespawn.linkboy&hl=en" pattern: '\[\[\["([^"]+)"\]\],\[\[\[\d+' author: "Pixel Respawn LLC" profiled_date: "2026-10-24" core_version: "4.0.0" version_basis: kind: package url: "https://play.google.com/store/apps/details?id=com.pixelrespawn.linkboy" artifact: "com.pixelrespawn.linkboy APK versionName (versionCode 95)" display_name: "Nintendo - Game Boy / Color / Advance (Linkboy)" mode: standalone cores: - "linkboy" - "Linkboy" - "LINKBOY" systems: - nintendo-gb - nintendo-gbc - nintendo-gba - nintendo-sgb notes: | Android package com.pixelrespawn.linkboy, closed source, free on Google Play with a paid unlock, reached by ES-DE through its LINKBOY find rule. Four Play distribution builds are read here, 4.0.0 (versionCode 95, minSdk 26, targetSdk 37, xapk sha256 9a10e00c6dcd2fdc66490000bf77bfa9846b37dffd31f8d96dc89d7c5997fee1), 3.11.4 (versionCode 93, minSdk 32, targetSdk 36, xapk sha256 4432cf9ab8ce2d148e8a0e89c26b786e4e7d060f43885d062f6d446b03ca4d32), 3.11.0 (versionCode 86, minSdk 26, xapk sha256 83b92276d28d71e491ebcbec3fa85cef42ef49d8ee0c6fd1bbe0045bc118f866) and 1.4.2 (versionCode 12), all carrying the app signing certificate sha256 feb643cfdd9c49f58eb325fde3d869cefcf59e45dfadb8e540beca35a7b1c28e and the Play distribution source stamp. Emulation lives in liblinkboy.so behind a JNI bridge. Addresses below are armeabi-v7a of 4.0.0 (liblinkboy.so sha256 86334694df475bfba4ec312ef69ca71e45dfda65e51eb074660ca177d80c88f3) and class names are those of its obfuscated dex. Four subsystems are declared: GBA, GBC, GB and SGB (rd0.java:16-21). An SGB cartridge runs in GB mode when prefer-sgb is off (y72.java:43, i71.java:203-205, 285-287). The three firmware images are the only files the emulator reads that it does not write itself. One table holds their names, sizes and md5 sums (uq.java:8), and the firmware screen reports each as present, mismatched or absent by comparing the size and then the md5 of the whole file (tq.java:22-85, t32.java:197-204). Importing a slot from that screen writes firmware/ and the name: a picked zip gives its first entry whose length equals the slot size, any other document is copied when its own length does (h.java:127-145, oq.java:58-167). Saves, cheats, thumbnails, keymaps and the ips, ups and bps patches picked up next to a ROM are written or supplied per game, not fixed files. An image is read only while the use-bios preference is on, which is off until set (y72.java:44, tf5.java:186-194, i71.java:207,289, b71.java:233). The loader appends /firmware/ and the name to the directory handed to setDataDir, the app's external files directory or its internal one when none is mounted (i71.java:74, qm3.java:32-41), and opens the result with fopen "rb". A file whose length is not exactly the expected size is closed and treated as absent, as is a short read. On success the loader returns the crc32 of the bytes (liblinkboy.so 0x1cb10-0x1cd1c, crc32 at 0x1c76c). A missing image stops nothing. The GBA path copies a 236 byte replacement bios compiled into the library over the 16 KB region and zero fills the remainder. Since 3.11.4 a second variant of that replacement is taken when the game code is B4GJ or B4SJ (0x10a22c-0x10a2c8). The GB and GBC path hands the reset routine a boot rom present flag, false when no image was loaded, and the machine starts from its post boot state (0x14f9b4-0x14fa38, 0x14fab8-0x14fad4). Since 3.11.4 a loaded GBA image is not run for every cartridge. When the ROM is at least 0xa0 bytes the crc32 of the 156 header bytes from offset 4 is compared with a fixed value, and a mismatch logs "Invalid logo, skipping BIOS" and resets with the boot flag false. The image stays installed and the machine starts from its post boot state (0x10a2ec-0x10a364). Save states record the crc32 of the image they were made under. Loading a state whose value differs from the running machine re-reads the file and refuses the state when the crc32 still disagrees (0x10aecc-0x10af24, 0x1501b0-0x1501bc, 0x150280-0x1502e4). files: - name: gba_bios.bin path: firmware/gba_bios.bin system: nintendo-gba required: false hle_fallback: true size: 16384 md5: a860e8c0b6d573d191e4ec7db1b1e4f6 validation: [size, md5] config_key: "use-bios" description: "Game Boy Advance BIOS" note: "Read into the 16 KB bios region when use-bios is on. Absent, mismatched in size or short, the region is filled with a replacement bios compiled into the library and zero padded. A cartridge whose header logo fails the crc32 test boots past it." source_ref: "Linkboy 4.0.0 uq.java:8, tq.java:22-85, liblinkboy.so 0x10a22c-0x10a2c8 (size argument 0x4000 at 0x10a260), 0x10a2ec-0x10a364 (logo test), loader 0x1cb10-0x1cd1c" - name: gbc_bios.bin path: firmware/gbc_bios.bin system: nintendo-gbc required: false hle_fallback: true size: 2304 md5: dbfce9db9deaa2567f6a84fde55f9680 validation: [size, md5] config_key: "use-bios" description: "Game Boy Color boot ROM" note: "Read when use-bios is on and the machine is a Game Boy Color. Without it the reset routine receives a false boot rom flag and the machine starts from its post boot state." source_ref: "Linkboy 4.0.0 uq.java:8, tq.java:22-85, liblinkboy.so 0x14fa20-0x14fa2c (size argument 0x900), 0x14fab8-0x14fad4, loader 0x1cb10-0x1cd1c" - name: gb_bios.bin path: firmware/gb_bios.bin system: nintendo-gb required: false hle_fallback: true size: 256 md5: 32fbbd84168d3482956eb3c5051637f5 validation: [size, md5] config_key: "use-bios" description: "Game Boy boot ROM" note: "Read when use-bios is on and the machine is a Game Boy. Without it the reset routine receives a false boot rom flag and the machine starts from its post boot state." source_ref: "Linkboy 4.0.0 uq.java:8, tq.java:22-85, liblinkboy.so 0x14fa0c-0x14fa18 (size argument 0x100), 0x14fab8-0x14fad4, loader 0x1cb10-0x1cd1c"