macOS
DMG Image Edit - R/W
It is quite easy to mount a DMG image in read/write mode. Say you want to copy something inside a read only DMG.
First mount the image in "read/write" mode (with shadow option), then when finished editing the DMG, convert/copy the changes made inside the shadow copy into another DMG.
How
- Open
Terminal.app
and mount the image with the shadow optionhdiutil attach -owners on Original.dmg -shadow
- Edit the DMG contents, when finished editing unmount the image
hdiutil detach /dev/disk#
Where # is the image's disk number (use: diskutil list to list them all)
- Now convert the shadow to a new DMG
hdiutil convert -format UDZO -o The_Edited.dmg Original.dmg -shadow
Output Formats
These are the image output formats you can choose from:
UDRW | UDIF read/write image |
UDRO | UDIF read-only image |
UDCO | UDIF ADC-compressed image |
UDZO | UDIF zlib-compressed image |
ULFO | UDIF lzfse-compressed image (OS X 10.11+ only) |
UDBZ | UDIF bzip2-compressed image (Mac OS X 10.4+ only) |
UDTO | DVD/CD-R master for export |
UDSP | SPARSE (grows with content) |
UDSB | SPARSEBUNDLE (grows with content; bundle-backed) |
UFBI | UDIF entire image with MD5 checksum |
UDRo | UDIF read-only (obsolete format) |
UDCo | UDIF compressed (obsolete format) |
RdWr | NDIF read/write image (deprecated) |
Rdxx | NDIF read-only image (Disk Copy 6.3.3 format; |
ROCo | NDIF compressed image (deprecated) |
Rken | NDIF compressed (obsolete format) |
DC42 | Disk Copy 4.2 image (obsolete format) |