ipsw

A guide to using the ipsw command-line tool to examine Apple firmware and software. Firmware is the low-level software shipped for devices such as iPhones and Macs.

In plain words
What is it for?
Use it to download or inspect IPSW and OTA files, analyze Mach-O programs, study iOS and macOS kernels, extract components, dump private API headers, compare firmware versions, and symbolicate crashes.
Why use it?
It organizes difficult Apple reverse-engineering tasks, from unpacking firmware to examining private system code and crash data.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/blacktop/ipsw-skill/ipsw
Any agent
npx skills add blacktop/ipsw-skill --skill ipsw
Clone the repo
git clone --depth 1 https://github.com/blacktop/ipsw-skill

Made for: Claude Code, Codex.

Per session 178 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,244 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00178 $0.03244
Opus 5 $0.00089 $0.01622
Sonnet 5 $0.00036 $0.00649
Haiku 4.5 $0.00018 $0.00324

Measured 2d ago against content hash 0a1bde3b4816, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ipsw scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

ipsw/SKILL.md · 313 lines

How it starts

The opening of the file, as written. The whole thing — 313 lines — stays where its author put it; the contents beside it link to each section on GitHub.

IPSW - Apple Reverse Engineering Toolkit

Install: brew install blacktop/tap/ipsw (Linux: see https://github.com/blacktop/ipsw#install)

Choose Your Workflow

Goal Start Here
Download/extract firmware Firmware Acquisition
Reverse engineer userspace Userspace RE
Analyze kernel/KEXTs Kernel Analysis
Research entitlements Entitlements
Dump private API headers Class Dump
Analyze standalone binary Mach-O Analysis
Diff two IPSWs/OTAs Firmware Diffing
Symbolicate a crash / panic Symbolication
Parse IMG4/AEA/iBoot/SEP Firmware Components
Decompile / query sandbox profiles Sandbox Profile Analysis
Inspect / mount an IPSW IPSW Inspection

Firmware Acquisition

# Download latest IPSW for device
ipsw download ipsw --device iPhone16,1 --latest

# Download with automatic kernel/DSC extraction
ipsw download ipsw --device iPhone16,1 --latest --kernel --dyld

# Extract components from local IPSW
ipsw extract --kernel iPhone16,1_18.0_Restore.ipsw
ipsw extract --dyld --dyld-arch arm64e iPhone16,1_18.0_Restore.ipsw

# Remote extraction (no full download)
ipsw extract --kernel --remote <IPSW_URL>

See references/download.md for device identifiers and advanced options.


Userspace RE (dyld_shared_cache)

macOS DSC location:

  • macOS 14+: /System/Volumes/Preboot/Cryptexes/OS/System/Library/dyld/dyld_shared_cache_arm64e
  • macOS 13 and earlier: /System/Library/dyld/dyld_shared_cache_arm64e

Examples below assume:

export DSC=/System/Volumes/Preboot/Cryptexes/OS/System/Library/dyld/dyld_shared_cache_arm64e

Essential Commands

Command Purpose
dyld a2s <DSC> <ADDR> Address → symbol (triage crash LR/PC)
dyld symaddr <DSC> <SYM> --image <DYLIB> Symbol → address
dyld disass <DSC> --vaddr <ADDR> Disassemble at address
dyld disass <DSC> --symbol <SYM> --image <DYLIB> Disassemble by symbol
dyld xref <DSC> <ADDR> --all Find all references to address
dyld dump <DSC> <ADDR> --size 256 Dump raw bytes at address
dyld str <DSC> "pattern" --image <DYLIB> Search strings
dyld objc --class <DSC> --image <DYLIB> List ObjC classes
dyld extract <DSC> <DYLIB> -o ./out/ Extract dylib for external tools

Read the full file on GitHub · 313 lines

Files

What ships with it

8 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 313 lines · 178 tokens per session scan A 0a1bde3b4816

Subscribe to this mod's changes

ipsw is a skill published in the GitHub repository blacktop/ipsw-skill (81 stars, last pushed 4mo ago), licensed MIT. It adds 178 tokens to every session and 3,244 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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