# Apple MacBook Air 5,2

This page describes how to run coreboot on MacBook Air 5,2, also known
as 13'' Mid 2012.

```eval_rst
+-------------+-------------+
| Model No.   | Motherboard |
+=============+=============+
| A1466       | 820-3209    |
+-------------+-------------+
```

## RAM configurations

This laptop comes with 6 different memory module variants. Not all of
them are supported at the moment. To determine which memory you have in your
MacBook Air 5,2, you can use inteltool and
[this script](https://github.com/gch1p/get_macbook_ramcfg). You need to run them
on the target machine.

First, build inteltool:
```console
$ cd util/inteltool
$ make -j4
```
Download the script and make it executable. Then run:
```console
$ sudo ./inteltool -g | /path/to/get_macbook_ramcfg -m mba52
```

You should get a name of RAM configuration installed in your MacBook. Use the
table below to determine if it's supported.
```eval_rst
+-------------------+-----------+
| RAM configuration | Supported |
+===================+===========+
| 4g_hynix          | **Yes**   |
+-------------------+-----------+
| 8g_hynix          | No        |
+-------------------+-----------+
| 4g_samsung        | No        |
+-------------------+-----------+
| 8g_samsung        | No        |
+-------------------+-----------+
| 4g_elpida         | No        |
+-------------------+-----------+
| 8g_elpida         | No        |
+-------------------+-----------+
```
If your RAM configuration is not supported, you can help supporting it. Run
`sudo inteltool -m`, save output to a text file and send a message to coreboot
[mailing list](/community/forums.html) specifying your memory configuration name
with the text file attached.

## Flashing instructions

### External flashing

The board has one 8 MiB flash chip. It's WSON-8 so using clip is not
possible. To access the chip, you need to remove the motherboard as
it's located on the bottom side of the board.

The other way to access the flash chip is by using **J5100 debug port**
on the board and an **SPI adapter**. To access the port, remove the back
cover.

![](mba52_motherboard.jpg)

To access SPI flash chip through the debug port, you need an adapter.
One of possible options is A4052 Chipmunk Easy Flash. To use this one,
you also need 8-pin JST-SH 1.0mm male cable that plugs into this adapter's
8-pin header on the other side.

![](mba52_adapter.jpg)

Connect the JST-SH cable's wires to your SPI programmer, **all except
VCC (3v3)**, then detach battery connector from the mainboard:

![](mba52_bat_unplug.jpg)

Plug the adapter:

![](mba52_plug_j5100.jpg)

The 3v3 pin of J5100 is not connected directly to the flash chip (U6100)
so it's not recommended to use it, as it's very unreliable and almost
never works. Instead, connect the 3v3 pin of your programmer to U7930's
3v3. It's wired directly to SPI chip:

![](mba52_3v3.jpg)

![](mba52_3v3_2.jpg)

Probe the chip with flashrom. If everything is set up correctly, flashrom
should detect the chip:

```
flashrom v1.1 on Linux 4.14.24-v7+ (armv7l)
flashrom is free software, get the source code at https://flashrom.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
Found Micron/Numonyx/ST flash chip "N25Q064..3E" (8192 kB, SPI) on linux_spi.
```

### Internal flashing

See [here](/flash_tutorial/int_macbook.md) how to flash coreboot internally when
running Apple EFI.

---

The flash layout of the OEM firmware is as follows:

```
00000000:00000fff fd
00190000:007fffff bios
00001000:0018ffff me
```

## Working

- 4 GiB (Hynix RAM) model
- Linux 4.9, Linux 5.10
- SeaBIOS
- GRUB
- Tianocore
- Wi-Fi
- S3 suspend and resume
- Both USB ports
- Trackpad
- libgfxinit
- me_cleaner
- Speakers
- ACPI support for battery, AC, lid (lid wakeup also works)
- SD card reader
- Camera
- Mic
- usbdebug (usb port on the left side)

## Untested

- Thunderbolt

## Known issues

- Bad sound in headphones.

## TODOs
- Support other memory configurations
- Fix headphones