EFI / UEFI Booting the Crucial / Micron M550 firmware update

Dual Channel Surfer

EFI / UEFI Booting the Crucial / Micron M550 firmware update

The firmware update for the Crucial/Micron M550 SSD now provides the firmware update tool for firmware MU02 implemented as a linux kernel and ramdisk contained in an ISO image.

Since we can boot a linux kernel using EFI, it should be possible to boot an Mac or UEFI pc from USB with an EFI bootloader and update the SSD firmware without an optical drive.


This EFI Boot USB method can also be used in cases where update from the optical drive fails.

Download link for GRUB-EFI bootloader files version 0.02 here:



More details including source code links and GPL license can be found in the grubefiusb-0.02.zip download from the link above.


Please note: using GRUB to boot the Micron firmware updater is unsupported.
Use this option at your own risk.


Installation procedure for OS X and other *nix:

1. Format the USB flash drive (in some cases an SD card can be used).

Format the USB flash drive as FAT32 (MS-DOS in OS X Disk Utility).
- use Partition Map type: Master Boot Record.
- select a volume name - in this case we use: EFIBOOT

Once formatting is complete, the volume should be mounted as EFIBOOT.

2. To install the EFI bootloader, open the folder containing the GRUB-EFI files:

 * EFI/boot/unicode.pf2
 * EFI/boot/bootx64.efi
 * EFI/boot/grub.cfg

Now copy the EFI folder and files to the root of the EFIBOOT USB.

3. Download the required Linux kernel and ramdisk and transfer to the USB.

MicroCore Linux 6.0 uses the following kernel and ramdisk file names:

 * boot/vmlinuz
 * boot/core.gz

The same file names are used in the Micron M550 SSD firmware update tool for firmware MU02. This might change for new SSD models and firmware releases.

4. Check the USB contents and edit the grub.cfg configuration file as needed.

The following files should now be found on our EFIBOOT USB:

 * EFI/boot/unicode.pf2
 * EFI/boot/bootx64.efi
 * EFI/boot/grub.cfg
 * boot/vmlinuz
 * boot/core.gz

5. Set the boot flag for the FAT32 partition (optional step).

This is an optional step and is not needed in most cases where an msdos partition table is used. There might be some EFI/UEFI implementations where
this is needed.

In Linux we can use the Gparted application to change the partition flags.

6. Shutdown/reboot the computer.

When restarting a Mac, press and hold the Option key at boot time.
In a few seconds, Startup Manager appears and you can select the USB device.

For some UEFI based motherboards, you might need to press F9, F12 or another key in order to select the correct boot device.

When the GRUB bootloader runs, the GRUB menu can be seen and the user can then select the preferred boot option using the up/down arrow keys.


* Micro Core Linux with waitusb=10 and superuser
* Micron Storage Director M550 FW update

If no key is pressed, the default menu option is used.



Mac users might prefer this instruction:



Please note: The Macrumors thread has been updated with information for updating the following firmware:

MX100 Firmware MU02

BX100 Firmware MU02


Some background information can be found in the M550 MU02 firmware thread:



Please note: feedback for the Crucial firmware itself and the official firmware update tools should be posted in that thread. This thread is just for info on EFI booting the firmware update.


Tags (4)
9 Replies
Dual Channel Surfer

Re: EFI/UEFI Booting the Crucial / Micron M550 firmware update

The original method using unix dd command still works and can still be used. However, the method in the first post of this thread and in the macrumors thread should be easier for most people.


Macrumors thread:



More info on using the dd method in this post.



The link to that older grub-efi image file grubefiusb.zip should still be available:



Dual Channel Surfer

Re: EFI/UEFI Booting the Crucial / Micron M550 firmware update

I've updated the EFI USB update to support the MX100 MU02 firmware update and tested this by updating an MX100 that was connected to the SATA port of a Gigabyte Z77-D3H UEFI motherboard. This successfully updated the MX100 512GB SSD from MU01 to MU02.


Please download the grubefiusb-0.03.zip file from the Macrumors thread attachment and follow the same instructions as with the M550 - obviously you also need to use the MX100 MU02 download from Crucial.


More details and the attachment are in the Macrumors thread:



Just like the M550 example, you should end up with the following files on a FAT32 formatted USB.

 * EFI/boot/unicode.pf2
 * EFI/boot/bootx64.efi
 * EFI/boot/grub.cfg
 * boot/vmlinuz
 * boot/core.gz


The files in the EFI/boot folder come from the grubefiusb-0.03.zip file.

The files in the boot folder come from the MX100 firmware update.



Edit: adding a direct download link to grubefiusb-0.03.zip in case the one in macrumors isn't available:



Tags (3)

Re: EFI/UEFI Booting the Crucial / Micron M550 firmware update

Dual Channel Surfer

Re: EFI/UEFI Booting the Crucial / Micron M550 firmware update

@summit48 wrote:


While I acknowledge that it would have taken some effort to produce this Topic .


The complexity of what has been posted in this Topic is just one of the reasons why Apple does not support third party SSDs,


Thanks for the feedback, but I feel the responsibility is mostly with the third party supplier. If Crucial promote their SSDs as being suitable for the Mac, then it would be reasonable for users to expect them to provide an EFI based firmware updater. Plus a lot of Windows machines default to UEFI these days.


On the positive side, at least these days Crucial / Micron provide a Linux based updater that can be booted in EFI mode. Some vendors are still providing their firmware in the form of a FreeDOS based update that can't be booted in EFI mode.



Re: EFI/UEFI Booting the Crucial / Micron M550 firmware update

Dual Channel Surfer

Re: EFI/UEFI Booting the Crucial / Micron M550 firmware update

>>>>>> So where is Micron/Crucial EFI updater for Mac?


I’m not Micron/Crucial. You can contact them here:


>>>>>> This is not strictly true, the Micron/Crucial updater support for UEFI boot mode is missing x64.


I’m not sure what you think is missing, but you don't need it to update Crucial SSD firmware on a 64 EFI machine.


***Edited to remove Crucial competitor***


I’d love to spend my free time responding to your multiple posts promoting other vendors, but I’d rather keep within the forum rules.


Crucial Employee

Re: EFI/UEFI Booting the Crucial / Micron M550 firmware update

Hi everyone,

Thank you for your posts.

I will personally pass your feedback on about the firmware update process.  We are always looking for ways to improve what we do and feedback like this does help.

If you do have any personal feedback you would like to provide then please contact me or the customer service team directly.

The Crucial Community Forums were created as a resource for Crucial customers, not as a place to vent frustrations or highlight negative experiences with Crucial products.  

We created our forums as a resource for Crucial memory product customers. For that reason, we do not allow discussions, positive or negative, of competing products or their suppliers by name on this forum. Posts or threads that mention competitors' names will be edited or deleted at our discretion, and company names will be filtered out from public view.


As mentioned by alex486 you can see the whole forum rules and guidelines here:  http://forum.crucial.com/t5/Forum-Rules-Guidelines/CRUCIAL-FORUMS-USAGE-GUIDELINES/td-p/117

Thank you all for your understanding and thank you for your awesome help and support.  


Crucial_Junket, Crucial Moderator, UK

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Kilobyte Kid

Re: EFI / UEFI Booting the Crucial / Micron M550 firmware update

Thanks. I was able to boot from USB on my MBP using this method. I'll also update the thread regarding M550 MU02 FW upgrade since this is what brought me here.


Instructions are simple.


Boot was a breeze


My MBP keyboard was recognized.


I run a mid 2011 MacBook Pro 13" 8Gb with M550 512Gb... now running MU02 FW (grin)


Thanks again.

Bit Baby

Re: EFI / UEFI Booting the Crucial / Micron M550 firmware update


These directions worked for me, with a 13" Early 2011 MacBook Pro, OS X 10.9.5 Mavericks