Before fixing the error, you must understand what your software is looking for. Apple does not use consumer-friendly names like "iPhone 7" or "iPhone 8" in its low-level firmware. Instead, it uses Model Identifiers and Hardware Suffixes.
3D101AP : This is the Board Configuration Number (also called the Hardware Model or Production Suffix). The 3D1 series refers to the iPhone 7’s D10 motherboard design. 01AP indicates a specific revision and region (GSM Intel variant). This code is etched onto the logic board and is used by low-level loaders to match the exact firmware components (like iBEC, iBSS, and LLB).
When a tool says loader for iphone9 3d101ap not found, it means:
Download Loaders or Firmware:
Ensure you are using the latest version of the software attempting the restore.
In the iOS jailbreak / low-level community, a loader is:
Common tools that use “loader” + device model: