Mac: divide USB into 2 partitions (for dashcam and music)

[evM3Sekar]

Inspired by the detailed post: [V9] How to Format USB into 2 Partitions for DashCam and Music [Windows] by @SomeJoe7777, I have created this post for mac. I did start out with windows, was able to create the 16gb partition for TeslaCam, and was unable to format the remainder for music because of "cannot be resized since there is 33mb of used space" error. Hence I resorted to the MacBook solution.

Goal: To have 1 single USB drive for both dashcam and music (recordings) without a Y-splitter USB cable.

System data:

• macOS Mojave 10.14.4
• Sandisk Extreme Go USB 3.1 128gb

Follow these steps:

1. Insert the USB drive (you will need a USB-3.1 to USB-c adapter on the latest MacBook Air)
   1. Launch Disk Utility from Applications folder.
2. Reformatting step 1 - create a Mac OS formatted disk:
   1. In the sidebar, choose the external USB drive.
   2. Click Erase from the menu near/on the title bar.
      
   3. In the Format drop-down menu, choose Mac OS Extended (Journaled) (Yes!).
   4. Enter a name for the volume (I called it M).
   5. Click Erase button, and then click Done.
3. Reformatting step 2 - partition to create a volume T:
   1. With the volume M selected in the sidebar, click Partition from the menu.
   2. Click the Add button (+) appearing below the blue pie chart to add a new partition.
   3. Enter a name (I called it T), size (16gb) and Format as MS DOS (FAT) (we're getting there).
   4. Click Apply (after volumes are properly specified), click Partition (to create partitions), and then click Done.
4. Reformatting step 3 - reformat M as MS DOS (FAT):
   1. With the volume M selected in the sidebar, click Erase from the menu.
   2. In the Format drop-down menu, choose MS DOS (FAT) (finally!).
   3. Click Erase button, and then click Done.
   4. I haven't tried but combining 4.1-4.3 as part of 3.3 should work as well.
5. Create the folder TeslaCam in volume T.
6. Use the USB stick in one of the 2 USB drives in the front cubby hole.
   1. The dashcam sign should pop-up near the right-top corner of the display.

Results:
Before I tested it out, I loaded some music onto the M drive. Everything worked as expected.

• Clips from the front dashcam, the left and the right repeater cams in 1 minute interval are available in the /T/TeslaCam/RecentClips folder.
• After returning from the test drive, I "downloaded" the last 10 minutes of the recording by pressing the dashcam icon. This gets saved into the /T/TeslaCam/SavedClips/DateXYZEtc folder.
• If you keep pressing the dashcam icon on the display for a few seconds, you will see a tiny expanding circle indicating that the recording has stopped. I did this and stop playing the music before I pulled out the stick. I don't seem to have any lost or corrupt data in my USB.
• Has been tested with music playing (from the USB) all the while.

I hope this helps!

 

[Neditor]

Thanks evM3! Helped me but I still had trouble getting the "Partition" option to be available.

SOLUTION:
After Step 1 above:
Disk Utility "View" drop down option in upper left corner must be changed from the default of "Show Only Volumes" to "Show All Devices".
Then click on the actual drive (and not the volume) to enable the partition selection options.

This may be obvious to many of you, but I struggled for a while before finding this solution so thought I would add for others.

For other amateurs like me I also learned:
Must use flash or SSD drives (not HDD) to work (someone may know how to use an HDD but it won't work with these standard instructions)
Make sure the folder "TeslaCam" has the upper case T and C as it is case sensitive.

 

[evM3Sekar]

Thanks evM3! Helped me but I still had trouble getting the "Partition" option to be available.

SOLUTION:
After Step 1 above:
Disk Utility "View" drop down option in upper left corner must be changed from the default of "Show Only Volumes" to "Show All Devices".
Then click on the actual drive (and not the volume) to enable the partition selection options.

This may be obvious to many of you, but I struggled for a while before finding this solution so thought I would add for others.

For other amateurs like me I also learned:
Must use flash or SSD drives (not HDD) to work (someone may know how to use an HDD but it won't work with these standard instructions)
Make sure the folder "TeslaCam" has the upper case T and C as it is case sensitive.

Thanks for pointing that out @Neditor. I should have recorded this line of instruction after Step 2.3 (can't seem to modify OP)

• 2.3a: Use GUID Partition Map Scheme (same as GPT on windows).

I can report back that if the dashcam is NOT turned off after you have parked, and pull out stick, the last set of files can be corrupted.
I can also confirm that when left on, dashcam continues to record (including left and right repeater) when the car is locked. When you get home in the evenings, or where you know it's safe like work, you may turn them off.

 

[supertvo]

@evM3Sekar
Thanks a lot. This saved me. I was struggling with the aforementioned Windows instruction.
Since I'm using macOS, I had to use my old Windows 8 VM to create partition using diskpart and got stuck at
Virtual Disk Service Error:
The operation is not supported in a non-empty removable disk.
Look like I might need to install Windows 10 to get around the error! This saves me so much time for that.

 

[supertvo]

To contribute back to community, I wrote this tool to help others:
mtrung/tesla-usb-drive

 

[yuxinhong]

Great tool, very easy to use thank you

 

[Paul8810]

To contribute back to community, I wrote this tool to help others:
mtrung/tesla-usb-drive

Thank you! Works perfectly.

 

[ralph142]

To contribute back to community, I wrote this tool to help others:
mtrung/tesla-usb-drive

perfect, thanks.

 

[lencap]

I very much appreciate the post, but try as I do it isn't working for me. The Partition box is greyed out. Using Mojave 10.14.5. I have an iXpand Flash Drive 32GB. I can set it up with a TeslaCam folder and it will record video as I drive, or for Sentry mode, but I can't partition the drive to accept music files. Following all the steps above I can't see the Partition options. Any ideas?

Also, I am using the right front USB port for the iXpand drive - and I've disconnected my second charging cable for my iPhone. I'd like to still use the iPhone charging cable, but if I plug the USB drive into any other USB port other than the front two that typically connect to the iPhone plugs, the video recording feature doesn't work.

It's been frustrating since I have a large music library. I don't know what else I can try - any thoughts?

 

[evM3Sekar]

I very much appreciate the post, but try as I do it isn't working for me. The Partition box is greyed out. Using Mojave 10.14.5. I have an iXpand Flash Drive 32GB. I can set it up with a TeslaCam folder and it will record video as I drive, or for Sentry mode, but I can't partition the drive to accept music files. Following all the steps above I can't see the Partition options. Any ideas?

If you are using the steps I posted above, can you complete up to step 2.5? If so, can you post pictures of what you see when you do 3.1 (with volume M selected)?

 

[sduck]

Pay extra attention to the parts in the instructions about what to select from the left side of disk utility - if you don't have the right thing selected, you won't get the partition options.

 

[planemechanic]

I am unable to get the partition option to be selectable. Started with a new thumbdrive, clicked erase then renamed it. After that I can't choose partition. Any ideas? TIA

 

[ralph142]

can you use the tool above? worked like a charm for me.

 

[bjelkeman]

To contribute back to community, I wrote this tool to help others:
mtrung/tesla-usb-drive

Thank you. That was helpful and made it all very easy.

 

[haffeli]

Inspired by the detailed post: [V9] How to Format USB into 2 Partitions for DashCam and Music [Windows] by @SomeJoe7777, I have created this post for mac. I did start out with windows, was able to create the 16gb partition for TeslaCam, and was unable to format the remainder for music because of "cannot be resized since there is 33mb of used space" error. Hence I resorted to the MacBook solution.

Goal: To have 1 single USB drive for both dashcam and music (recordings) without a Y-splitter USB cable.

System data:

• macOS Mojave 10.14.4
• Sandisk Extreme Go USB 3.1 128gb

Follow these steps:

1. Insert the USB drive (you will need a USB-3.1 to USB-c adapter on the latest MacBook Air)
   1. Launch Disk Utility from Applications folder.
2. Reformatting step 1 - create a Mac OS formatted disk:
   1. In the sidebar, choose the external USB drive.
   2. Click Erase from the menu near/on the title bar.
      
   3. In the Format drop-down menu, choose Mac OS Extended (Journaled) (Yes!).
   4. Enter a name for the volume (I called it M).
   5. Click Erase button, and then click Done.
3. Reformatting step 2 - partition to create a volume T:
   1. With the volume M selected in the sidebar, click Partition from the menu.
   2. Click the Add button (+) appearing below the blue pie chart to add a new partition.
   3. Enter a name (I called it T), size (16gb) and Format as MS DOS (FAT) (we're getting there).
   4. Click Apply (after volumes are properly specified), click Partition (to create partitions), and then click Done.
4. Reformatting step 3 - reformat M as MS DOS (FAT):
   1. With the volume M selected in the sidebar, click Erase from the menu.
   2. In the Format drop-down menu, choose MS DOS (FAT) (finally!).
   3. Click Erase button, and then click Done.
   4. I haven't tried but combining 4.1-4.3 as part of 3.3 should work as well.
5. Create the folder TeslaCam in volume T.
6. Use the USB stick in one of the 2 USB drives in the front cubby hole.
   1. The dashcam sign should pop-up near the right-top corner of the display.

Results:
Before I tested it out, I loaded some music onto the M drive. Everything worked as expected.

• Clips from the front dashcam, the left and the right repeater cams in 1 minute interval are available in the /T/TeslaCam/RecentClips folder.
• After returning from the test drive, I "downloaded" the last 10 minutes of the recording by pressing the dashcam icon. This gets saved into the /T/TeslaCam/SavedClips/DateXYZEtc folder.
• If you keep pressing the dashcam icon on the display for a few seconds, you will see a tiny expanding circle indicating that the recording has stopped. I did this and stop playing the music before I pulled out the stick. I don't seem to have any lost or corrupt data in my USB.
• Has been tested with music playing (from the USB) all the while.

I hope this helps!

This is very helpful, thanks for the post.

 

[lschult2]

For those of you saying the the Partition box is greyed out, be sure the Scheme is GUID Partition Map and not Master Boot Record.

 

[bassbone57]

I had a similar issue with Disk Utility and the greyed out partition button. Used this in terminal instead, where:
/dev/disk2 is the full path to your external drive, which you can find out by going diskutil list

VIDEO where I'll put the TeslaCam folder and MUSIC is where I'll store all of my music.



diskutil partitionDisk /dev/disk2 2 MBR FAT32 VIDEO 50% FAT32 MUSIC R


So you use this in place of steps 1-4 above.

 

[KenC]

Can the partitions be ExFat, or must they be MSDosFat?

And, why do you need two partitions anyway? Why can't the music be in the same partition with the TeslaCam folder?

 

[srs5694]

Can the partitions be ExFat, or must they be MSDosFat?

For music, you can use either FAT or ext2/3/4fs. Tesla uses a Linux variant inside the car, and Linux has no native in-kernel exFAT driver because that's a proprietary filesystem on which Microsoft owns several patents. (There are non-kernel exFAT drivers for Linux, but the Linux kernel developers are understandably skittish about such things.) FAT is essentially free to use and so is not a problem, and the ext# filesystems are Linux-native filesystems.

For some reason, Tesla supports only FAT for the TeslaCam partition. In theory, ext2/3/4fs could be made to work, too, but for some reason I don't know, Tesla's developers chose to restrict it to FAT.

Unfortunately, this sort of thing is common. FAT is ancient and limited, but it's widely supported. Microsoft would like people to move on to exFAT (or perhaps NTFS), Apple would like people to move on to HFS+ (or now APFS), and companies building tools around Linux would like people to move on to ext2/3/4fs. Unfortunately, the proprietary/patent-encumbered natures of exFAT and NTFS make them a tough sell for anything built on open source software; HFS+ and APFS are very Mac-centric and poorly supported outside of that ecosystem; and although ext2/3/4fs are open source and therefore free to use, the tools to support them in Windows are awkward, so nobody wants to force Windows users to use this filesystem family. Thus, we're stuck with FAT, and probably will be for a while, short of a breakthrough like Microsoft un-encumbering exFAT of its patents.

And, why do you need two partitions anyway? Why can't the music be in the same partition with the TeslaCam folder?

The answer to this "why" question would require access to the source code and/or internal Tesla company communications. I don't know of an official explanation. In fact, IIRC, Tesla's owner manuals don't even mention partitioning the disk; they say you need two separate devices to have both music and TeslaCam functionality. AFAIK, Tesla has made no official statement in answer to your question, and in the absence of such a statement, we can only speculate. I'll refrain from doing so, since I have no strong reason to think the reason might be anything in particular.

 

[sduck]

For some reason, Tesla supports only FAT for the TeslaCam partition. In theory, ext2/3/4fs could be made to work, too, but for some reason I don't know, Tesla's developers chose to restrict it to FAT.

Update to this very helpful post - as of one of the recent updates, you can use ext4 for the dashcam partition also. I've tried it; it works. You still need two partitions though, which is still annoying. And if they're both ext4, it sometimes confuses the USB audio system, and you lose your place over power cycles. I tried throwing the TeslaCam folder and some music into a drive with just one ext4 partition, and it didn't work. So, I've gone back to having the dashcam partition being fat32, and the music partition being ext4.