macOS Bootloader Not Respecting Custom Drive Icons After Latest Firmware Update

[Takuro]

On a 2020 iMac, after installing macOS Big Sur 11.3, the macOS boot loader is no longer respecting custom drive icons for any internal or external storage. I have verified that .VolumeIcon.icns properly exists on the root of drives with custom icons set. Attached is a photo of an iMac facing the issue where a USB drive titled "Big Sur" is showing the default icon for external storage devices. By comparison, a second photo shows the exact same USB drive attached to a 2019 MacBook Pro that isn't seeing the issue so far. The iMac's PRAM and SPRAM have both been reset with no change in behavior.

Update: So when I tried to boot the Big Sur USB drive from my MacBook, it said a firmware update was required to use the drive. I guess it's been a while since I tried to boot that disk from that laptop. After it re-flashed its firmware, it has the exact same problem. I guess Apple broke custom drive icons in a firmware update they are gradually pushing to Intel Macs. I've filed a bug report, and hopefully it gets fixed.

 

[DIY_glenn]

Any update? 11.4 did no difference.

 

[Takuro]

This bug is gradually being fixed in the macOS Monterey betas. In beta 1, it prompted my MacBook Pro to undergo a firmware update which fixed the issue. In beta 4, it prompted my iMac for a firmware update which also fixed this.

So the bad news is: They may never fix this in Big Sur. But even if you load Monterey on a thumb drive and boot it off USB, that's enough to kick off the firmware update, and the fix will persist no matter what OS you actually load.

 

[tinygoblin]

Does anyone happen to know if the custom .VolumeIcons.icns for partitions have been fixed in any updates of macOS Big Sur, i.e. 11.5, 11.6, etc.? Maybe somebody remembers seeing multiple reboots during update (that usually indicates EFI firmware update).

Takuro, thanks for valuable notes regarding the issue, it's been driving me mad and I've tried every folder on my EFI partition for .VoluemIcon.icns. To make things worse I cannot update to macOS Moneterey (file is almost 13 GB!) at all since the drive space is insufficient and even applying Big Sur downloadable update is a lot of preparation work (11.6.4 is like 3 GB only for download, that's nuts!).

I've found some observations similar to Takuro's about the problem in this article and some explanation, however the article never updated with a current status of a problem in later macOS Big Sur updates:

Finder will not show, nor allow you to set custom icons on other Catalina and Big Sur startup disks
Finder will show and allow you to customize the volume icon for your current startup disk, but not for other Catalina- or Big Sur-bearing startup disks that your Mac is not currently booted from. This problem is not specific to CCC backups, but we see this frequently because CCC creates bootable backups. This problem is the result of a design flaw in the implementation of custom icons in an APFS volume group. Up to macOS Catalina, the custom volume icon is stored in a file at the root of the startup disk named ".VolumeIcon.icns". To keep the System volume read-only, yet allow the apparent modification of this icon file, Apple chose to create a symbolic link at the root of the startup disk that points to System/Volumes/Data/.VolumeIcon.icns. For the current startup disk, this path resolves correctly because the Data member of the volume group is mounted at /System/Volumes/Data. That's not the case for external volumes, those Data volumes are mounted at /Volumes/CCC Backup - Data (for example). As a result, the symbolic link to .VolumeIcon.icns is unresolvable for any volume that is not the current startup disk.
We have reported this issue to Apple (FB7697349) and we are currently awaiting a response.

Other Catalina and Big Sur startup disks can't be renamed in the Finder
Finder will let you rename the current startup disk, but you won't be able to rename any other startup disks that have an installation of Catalina or Big Sur because the System volume is mounted read-only.
Solution: Unmount and remount the volume in Disk Utility, then right-click on the volume in Disk Utility's sidebar and choose the option to rename the volume.
We have reported this issue to Apple (FB8912480) and we are currently awaiting a response.

I've also found this guide explaining how to fix APFS drive icon in Big Sur but nothing regarding other types of drives.

I'm experiencing this problem in macOS 11.3.1 Big Sur on 2019 16-inch MacBook Pro. My ultimate goal is to replace Boot Camp partition icon because currently it displays low-resolution Boot Camp Assistant icon and it looks awful. I'm able to change partition labels shown on boot though.

 

[tinygoblin]

On a side note, would someone who's running T2-equipped Mac on macOS 11.6.3 or later report if the custom icons issue was fixed in EFI version 1715.81.2.0.0 (which happen to be latest Boot ROM versions for macOS Big Sur according to ELC article)? You can see EFI version using Terminal command "system_profiler SPHardwareDataType" or using Apple > About this Mac > More Info > Contents.

P.S. Why my answers are always moderated for like 24 hours? It should be quite clear I'm a human being with some specific Mac-related topic to discuss...

 

[tinygoblin]

I think it's worth noting this was indeed a bug that was fixed in later versions of EFI firmware or iBridge, so the fix was updating macOS from 11.3.1 to something else (i.e. 11.6.1). Firmware updates come along with macOS Big Sur updates.

 

[boredandlonely]

[deleted, had different issue]