UA1ZBE Custom Firmware v1.0

Features:
- VFO mode with direct frequency input
- POCSAG decoder (512/1200 baud) with BCH(31,21) correction
- Full-screen Spectrum analyzer
- FM Radio receiver
- RSSI signal indicator overlay
- Custom boot splash (UA1ZBE / POCSAG pager / build date)

Architecture:
- app/mode.c — mode dispatcher (VFO/POCSAG/Spectrum/FM)
- app/boot_splash.c — 2-second boot splash
- app/pocsag/ — POCSAG decoder + BCH correction
- app/display_rssi.c — RSSI indicator
- main.c — entry point with custom init
- syscalls.c — bare-metal _sbrk stub

Build: arm-none-eabi-gcc -Os -flto -Wall -Werror -Wextra
Size: 57.9KB Flash / 3.6KB RAM

Controls:
- 0-9: Direct frequency input (VFO)
- SK2: POCSAG mode
- SK1: Spectrum analyzer
- 0: FM Radio
- EXIT: Return to VFO
- F/*: Toggle 512/1200 baud (in POCSAG)

bitmaps.h

@@ -0,0 +1,51 @@
+
+#ifndef BITMAP_H
+#define BITMAP_H
+
+#include <stdint.h>
+
+extern const uint8_t BITMAP_POWERSAVE[8];
+extern const uint8_t BITMAP_TX[8];
+extern const uint8_t BITMAP_RX[8];
+extern const uint8_t BITMAP_FM[10];
+extern const uint8_t BITMAP_BatteryLevel[2];
+extern const uint8_t BITMAP_BatteryLevel1[17];
+
+extern const uint8_t BITMAP_USB_C[9];
+
+extern const uint8_t BITMAP_KeyLock[6];
+
+extern const uint8_t BITMAP_F_Key[6];
+
+#ifdef ENABLE_VOX
+	extern const uint8_t BITMAP_VOX[18];
+#endif
+
+extern const uint8_t BITMAP_XB[12];
+
+extern const uint8_t BITMAP_TDR1[16];
+extern const uint8_t BITMAP_TDR2[10];
+
+#ifdef ENABLE_VOICE
+	extern const uint8_t BITMAP_VoicePrompt[9];
+#endif
+
+#ifdef ENABLE_NOAA
+	extern const uint8_t BITMAP_NOAA[11];
+#endif
+
+extern const uint8_t BITMAP_Antenna[5];
+
+extern const uint8_t BITMAP_VFO_Default[8];
+extern const uint8_t BITMAP_VFO_NotDefault[8];
+
+extern const uint8_t BITMAP_ScanList1[6];
+extern const uint8_t BITMAP_ScanList2[6];
+
+extern const uint8_t BITMAP_compand[6];
+
+#ifndef ENABLE_CUSTOM_MENU_LAYOUT
+	extern const uint8_t BITMAP_CurrentIndicator[8];
+#endif
+
+#endif