This HAT adds a second micro SD socket to your Raspberry Pi.

Being able to plug in a second micro SD card opens up a variety of interesting possibilities, such as:

• A micro SD card reader! Write new images, repair or modify existing Raspberry Pi installations with ease.
• Additional storage - mount as your home directory, for general storage or backups.
• RAID1 on the root (/) partition for added reliability.
• Connector for Controller Serial Console using our USB Serial Adaptor.

Please note: MMC HAT is only supported on Raspberry Pi OS at present

Compatibility

Compatible with

• Raspberry Pi A+
• Raspberry PI B+
• Raspberry Pi Zero & Zero W¹ (with headers)
• Raspberry 2B
• Raspberry Pi 3B¹ & 3B+¹
• Raspberry Pi 4B

¹When used on a Raspberry Pi Zero W, 3B or 3B+ the on-board WiFi is disabled as it is on the SDIO interface used by the MMC HAT

The Raspberry Pi 4 has three SD controllers so you can use onboard SD, WiFi and the MMC HAT (SD) at the same time on the Pi4!

When using a Raspberry Pi 4 please add the following three lines to the TOP of the config.txt file in the boot directory.

[pi4]

dtparam=mmchat_pi4

[all]

Performance

With the standard SD clock speed a micro SD card in the MMC HAT (/dev/mmcblk2) performs at similar speeds to the onboard micro SD card (/dev/mmcblk0).

Included

• 1 x MMC HAT
• 4 x 12mm M2.5 standoff
• 8 x 6mm M2.5 screw
• 4 x stick on foot