amiga-bootcamp/02_boot_sequence/early_startup.md
Ilia Sharin 21751c0025 docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections
Comprehensive technical documentation covering:
- Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives
- Boot sequence: cold boot through startup-sequence
- Binary format: HUNK executable spec, relocation, debug info
- Linking & ABI: .fd files, LVO tables, register calling conventions
- Exec kernel: tasks, interrupts, memory, signals, semaphores
- AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting
- Graphics: planar bitmaps, Copper programming, HAM/EHB modes
- Intuition: screens, windows, IDCMP, BOOPSI
- Devices: trackdisk, SCSI, serial, timer, audio, keyboard
- Libraries: utility, expansion, IFFParse, locale, ARexx
- Networking: bsdsocket API, SANA-II, TCP/IP stack comparison
- Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging
- Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies
- CPU & MMU: 68040/060 emulation libs, PMMU, cache management
- Driver development: SANA-II, Picasso96/RTG, AHI audio

All files include breadcrumb navigation. No local paths or proprietary content.
2026-04-23 12:17:35 -04:00

1.7 KiB

← Home · Boot Sequence

Early Startup Control — Boot Options

Overview

The Early Startup Control (ESC) menu appears when both mouse buttons are held during power-on or reset. It provides boot device selection, display mode override, and emergency recovery options.


Activation

  • Both mouse buttons held before the boot screen hand animation completes
  • On A1200: hold both buttons during "floppy click" phase
  • Requires Kickstart 2.0+ (not available on 1.3)

Menu Options (OS 3.1)

┌──────────────────────────────────┐
│     EARLY STARTUP CONTROL        │
│                                  │
│  Boot With No Startup-Sequence   │
│  Boot Standard                   │
│                                  │
│  Boot Device:                    │
│    DF0:  (pri 5)                 │
│    DH0:  (pri 0)                 │
│                                  │
│  Display Mode:                   │
│    ● PAL   ○ NTSC                │
│                                  │
│          [BOOT]                  │
└──────────────────────────────────┘

Recovery Scenarios

Scenario Fix
Corrupted Startup-Sequence Boot with No Startup-Sequence, then ED S:Startup-Sequence
Wrong display mode (no image) Hold both buttons → change PAL/NTSC
Boot from floppy instead of HD Select DF0: as boot device
Assign loops / infinite boot No Startup-Sequence → fix assigns manually

References

  • RKRM: Early Startup chapter
  • OS 3.1 AmigaGuide: System/BootMenu