More than a decade later, we finally see the giant red development board that was the original iPhone prototype

In October 2017, Apple released the iPhone X, a tribute to the 10th anniversary of the iPhone. This phone integrates many advanced technologies, whether it is the full-screen with equal width on all four sides, or the Face ID that achieves payment-level security for facial recognition. The iPhone X is undoubtedly the most advanced phone of the year, just like its earliest predecessor, the first generation iPhone, was born ten years ago.

Let's go back in time to the first time we saw the magical touch interface that scrolled with inertia when sliding your finger and had a rebound effect when it reached the top and bottom.

I have been waiting for this day for two and a half years.

So said the late Apple CEO Steve Jobs when he launched the iPhone on January 9, 2007.

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During these two and a half years, Apple had been secretly developing the iPhone. We have since learned about the development history of the iPhone from various reports. For example, there was a P1 plan based on the iPod at the time, and the full-touch phone we saw later was the P2 plan. The latter won and shook the whole world.

For many people inside Apple, the iPhone is so mysterious that they only know its development codenames as "M68" and "Purple 2". But more than ten years later, we finally have the opportunity to see what this great phone looked like before it was finally completed and quietly lay on a red circuit board.

Today, The Verge publicly displayed the development circuit board of the first-generation iPhone, which provides a valuable historical perspective - how the iPhone, which changed the mobile phone industry ten years ago, was made.

The iPhone in its development board form was far from having the addictive power it later had. At that time, the iPhone did not have those insights into human nature, but only cold component modules, like a dormant robot that had not yet been infused with the system.

Almost all the components of the iPhone are integrated on this development board, which are arranged in various places on this development board. At first glance, this red iPhone M68 motherboard looks like a computer motherboard that was everywhere more than ten years ago. The size of this development board is incomparable with the Qualcomm prototype development board we have seen in recent years, and the size of the iPhone M68 development board is actually close to that of a PC motherboard.

In order to keep the first generation of iPhone confidential, Apple engineers developed this special circuit board to test the software and radio parts, also known as the EVT (Engineering Verification Test) sample, so that developers would not know the final form of the iPhone. In addition, Apple only used red circuit boards when developing prototype iPhones, and would prefer blue, green or other colors in the production stage.

This prototype development board does have many similarities to a PC motherboard, such as a serial connector on the top for testing iPod accessories, the classic 30-pin interface used by the original iPhone, and even a LAN port on the development board. There are also two mini USB ports on the side of the board, so that Apple engineers can code for the device through these ports without looking at the screen.

What many engineers still need to do is to port Apple's underlying Darwin operating system to the iPhone. Darwin is a Unix-based operating system that includes a set of core drivers that can provide support for almost all Apple systems including macOS, iOS, watchOS, tvOS and audioOS. Apple calls Darwin developers "core operating system engineers". They are responsible for the kernel, file system, device drivers, processor structure and many other important low-level tasks to ensure that these most core hardware can be connected and run.

If you look at the top, the typical difference between the iPhone prototype board and the PC motherboard is revealed. There is a SIM card slot on the top of the development board, and there are two antennas for Wi-Fi and Bluetooth connections nearby. They are connected to the main wireless I/O board, which is similar to the structure of the first generation iPhone that was finally shipped. There are chips from Intel, Infineon, CSR, and Marvell on the radio circuit board. These chips also show that Apple needs to work closely with multiple chip manufacturers to launch the iPhone.

In addition, there is an RJ11 interface on the right side of the circuit board, which is the interface used by landline phones. Engineers can connect landline phone lines to this development board to test voice. Nowadays, we can already make calls with Apple Watch, but imagine what it would be like to make calls with the prototype development board of iPhone in 2006.

The middle part is the core of the development board, including the processor used by the prototype. Apple used some components of Samsung K4X1G153PC, a 620MHz ARM processor (ARM1176JZF) to run the iPhone operating system, and used PoP stacking packaging, with the CPU packaged at the bottom and the memory packaged at the top. It is then connected to a Samsung 4GB NAND card to store the operating system. The green NAND storage module can be easily removed by developers, and then a new card can be inserted to quickly test different operating system versions.

There is even a screen on this board, but its Home button (here called the menu button) is installed on the motherboard to the left of the display, and the power button and volume button are also on the left of the display. If we start this prototype, the Apple logo will light up, and engineers will test the kernel through the command line. In addition, the source said that if the development board is connected to iTunes through the 30-pin interface on the side, it will show that an iPhone that can be restored is detected.

There are many white connectors with pins in other places on the motherboard. The smaller one is the JTAG connector for low-level debugging. Engineers can connect signal probes to monitor various signals and voltages to ensure that the iPhone's software adjustments will not affect the hardware. There are also various DIP switches around to control the debugging signals for more in-depth testing.

If Apple engineers use such a development board without a screen, they can connect to a display through the component RCA interface on the side of the board. There is also a stereo output interface on the side. Engineers can also use it to test the connection with headphones. Even the iPhone main camera is installed on the board for testing. There is also a huge space for testing the battery part. If the engineer does not connect the battery, the DC interface on the top can be connected to an external power supply. Apple even leaves room for testing the distance sensor marked as "pro flex".

As you can see from this development board, Apple engineers had considered almost everything before launching the iPhone. Development boards like this one may have been used from 2006 to 2007 until the iPhone was released.

Today, Apple no longer needs such a huge development board to develop new iPhones. As early as the iPhone 4, it has used a smaller motherboard. The latest models are even equipped with large and bulky security covers to keep the final design of the hardware confidential. Many other mobile phone manufacturers now use similar methods to maintain confidentiality.

This early development board also reminds us of the enormous workload and confidentiality required to create a portable device used by millions or even hundreds of millions of people. It is difficult for us to see early development boards like this one now, especially after more than ten years, which makes it even more precious.