Cannot access Ventoy disk when booted using Ventoy

Cannot access Ventoy disk (where all the ISOs are stored) when booted into helloSystem from Ventoy:

```
% sudo mount.exfat /dev/ada1p1 /mnt
FUSE exfat 1.3.0
WARN: '/dev/ada1p1' is write-protected, mounting read-only.

% sudo fsck.exfat /dev/ada1p1
exfatfsck 1.3.0
Checking file system on /dev/ada1p1.
ERROR: failed to open '/dev/ada1p1' in read-write mode: Operation not permitted.
File system checking stopped. ERRORS FOUND: 1, FIXED: 0.
```

Why is this?

I think I have seen this work before (on GhostBSD or an older helloSystem ISO)? I will need to test again.

@ventoy is this a known limitation? Any way around it?