# Process to change .iso image



## rpowell47 (Jun 5, 2022)

I've downloaded an .iso image that is read only. Thus, when I burn it on a dvd, it will not boot my pc. Is there a procedure to change it or is the read/only image none changeable except from the original source?


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## Alain De Vos (Jun 5, 2022)

Do you expect an answer ?


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## stratact (Jun 6, 2022)

rpowell47 said:


> I've downloaded an .iso image that is read only.


Aren't all ISO image files read-only, since the ISO 9660 filesystem used to mount them is read-only?



rpowell47 said:


> Thus, when I burn it on a dvd, it will not boot my pc.


Possibly a misconfigured BIOS boot order or settings?



rpowell47 said:


> Is there a procedure to change it or is the read/only image none changeable except from the original source?


You would want to mount the image somewhere and copy its contents to another directory. After changing what you need inside that directory, create a new ISO from it for burning to another DVD.

Go to 18.5. Creating and Using CD Media and then scroll down to section *18.5.3.*


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## rpowell47 (Jun 6, 2022)

Possibly a misconfigured BIOS boot order or settings? I appreciate your comments. I believe that is the issue.


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## smithi (Jun 6, 2022)

stratact said:


> You would want to mount the image somewhere and copy its contents to another directory. After changing what you need inside that directory, create a new ISO from it for burning to another DVD.
> 
> Go to 18.5. Creating and Using CD Media and then scroll down to section *18.5.3.*


It may not be that simple.  If it's a FreeBSD boot image for CD or DVD, looking at
/usr/src/release/amd64/mkisoimages.sh
shows there's more to it, and that mkimg(1) is used rather than mkisofs.

Use file(1) and etdump(8) to check which options a particular .iso contains.

I also want to write back some patched files to the 12.3-RELEASE amd64 dvd1 .iso, hence recently diving down this rabbit hole - but I'm far from confident on how to do this yet myself ...


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## Alain De Vos (Jun 7, 2022)

You can mount an .iso with loopback "mdconfig", then "mount -t cd9660" then you can use read write, add packages etc ...
For .img i'm not so certain ...


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## chessguy64 (Jun 7, 2022)

rpowell47 said:


> Possibly a misconfigured BIOS boot order or settings?



If your hard drive is set as the first boot device, the dvd will not boot the installer/ live dvd 

It has nothing to do with the ISO being read only. And you can hit a FN key to select boot device during boot.


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## smithi (Jun 7, 2022)

Alain De Vos said:


> You can mount an .iso with loopback "mdconfig", then "mount -t cd9660" then you can use read write, add packages etc ...
> For .img i'm not so certain ...


I've read that elsewhere Alain, but I can not get it to work.

play.iso is a (rw) copy of FreeBSD-12.3-RELEASE-amd64-dvd1.iso:

```
mdconfig -o noreadonly -S 2048 -u 7 -f play.iso
mdconfig -l -u7
```
works, and using dd I've confirmed that writing to /dev/md7 updates play.iso as expected.

However neither `mount -t cd9660 -o w ...` nor `mount_cd9660 -o rw ...` succeed, despite the example for the Photo-CD in mount_cd9660(8)

Have you (or has anyone?) succeeded in mounting a cd9660 image read/write?

If so, please show the mount command used in context?

TIA, Ian


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## rpowell47 (Jun 7, 2022)

chessguy64 said:


> If your hard drive is set as the first boot device, the dvd will not boot the installer/ live dvd
> 
> It has nothing to do with the ISO being read only. And you can hit a FN key to select boot device during boot.


Thanks, I have, many times, set my BIOS to select only the cd/dvd drive to no avail. (I'm assuming the FN means function keys) I tried that many times too.


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## chessguy64 (Jun 7, 2022)

It's hard to say what the problem is unless you post more info. (what tool you used to burn the dvd, what .iso image you used, did you try burning a fresh dvd and booting from that? etc.) You can get bad CD/DVDs in a batch, so that might be why it's not booting. Did you try burning the image to one or more fresh dvds? You have to post more info here because it could be a number of things why your dvd isn't booting.


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## rpowell47 (Jun 7, 2022)

chessguy64 said:


> It's hard to say what the problem is unless you post more info. (what tool you used to burn the dvd, what .iso image you used, did you try burning a fresh dvd and booting from that? etc.) You can get bad CD/DVDs in a batch, so that might be why it's not booting. Did you try burning the image to one or more fresh dvds? You have to post more info here because it could be a number of things why your dvd isn't booting.


1. xfburn (mate)
2. Used at least 4 new dvd's
3. Used xfburn to Blank and a long slow format procedure
4. dban-2.3.0_i586.iso also tried ADRIANE-KNOPPIX_V7.2.0bootonly-2013-07-28-EN.iso and a few other .iso
5. cd0 at ahcich4 bus 0 scbus4 target 0 lun 0
cd0: <HL-DT-ST DVDRAM GH24NSC0 LY00> Removable CD-ROM SCSI device
cd0: Serial Number KMUK5E83725
cd0: 150.000MB/s transfers (SATA 1.x, UDMA6, ATAPI 12bytes, PIO 8192bytes)
cd0: 0MB (1 0 byte sectors)
6. MSI Z590 PRO WI-FI PRO Motherboard with the BIOS first choice drive to boot from UEFI cd/dvd all the other other boot options are disabled

I appreciate your time and am very happy to somehow find a solution. Also, I purchased a new ASUS Model DRW-24B1ST-N28 drive but have not installed it yet.


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## msplsh (Jun 7, 2022)

First: Can you boot any other disc?  If so, there's probably an issue with how it was burnt, which can extend to burning an image that was corrupted on download.


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## rpowell47 (Jun 7, 2022)

msplsh said:


> First: Can you boot any other disc?  If so, there's probably an issue with how it was burnt, which can extend to burning an image that was corrupted on download.


Yes, any of my .iso disk still will boot. Those .iso listed in #11 simply will not boot. Nevertheless, when burning those with xfburn the process is carried out as if successful. But, that does not mean that the burn actually did burn it; I'm assuming. I'm going to shut down now  and install the new ASUS drive and see if that will make any difference. 
Thanks for you thoughts.


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## chessguy64 (Jun 7, 2022)

rpowell47 said:


> 4. dban-2.3.0_i586.iso also tried ADRIANE-KNOPPIX_V7.2.0bootonly-2013-07-28-EN.iso and a few other .iso



You are burning very small CD .iso images to DVDs. That knoppix .iso is only 7.7MB. Why waste a DVD for that? Try burning live CD images to CDs like they were intended. Even though the dvd might burn successfully, it doesn't really make sense to do what you are doing. I'm guessing it's some type of compatibility / formatting issue that when your computer reads from the dvd drive, it's expecting to boot a cd image off a CD drive, not a dvd drive.. and this is where you are having problems. Try burning to CDs and see what happens.


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## rpowell47 (Jun 7, 2022)

chessguy64 said:


> You are burning very small CD .iso images to DVDs. That knoppix .iso is only 7.7MB. Why waste a DVD for that? Try burning live CD images to CDs like they were intended. Even though the dvd might burn successfully, it doesn't really make sense to do what you are doing. I'm guessing it's some type of compatibility / formatting issue that when your computer reads from the dvd drive, it's expecting to boot a cd image off a CD drive, not a dvd drive.. and this is where you are having problems. Try burning to CDs and see what happens.


Thanks for your thoughts. I just carried out your idea with a new CD-RW 700mg with absolutely the same results. No Boot. Have some domestic duties now - So talk with you later.
Again, Thanks.


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## astyle (Jun 7, 2022)

Most CD/DVD burning apps have an option to burn it as a bootable disc. You do need to hunt around a bit to find that.

I personally would recommend using a USB stick, and boot off that.


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## chessguy64 (Jun 7, 2022)

What about on a CD-R disc ? IIRC I had some issues booting a live cd when I burned it to a cd-rw in the past.

And yeah, what astyle said. Much faster read/write speeds and less chance for errors.


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## astyle (Jun 7, 2022)

chessguy64 said:


> What about on a CD-R disc ? IIRC I had some issues booting a live cd when I burned it to a cd-rw in the past.


I last used THAT in 2015, I think. IIRC, the quality of the disc matters more than whether it's CD-R or CD-RW. If you  have something brand-new, it shouldn't matter which one you use. Basically, have a good, bootable ISO file first, and then burn it correctly.


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## Alain De Vos (Jun 7, 2022)

I don't have UEFI on my PC so i'm unable to test some things.
Script below might give some ideas,

```
wget https://download.freebsd.org/releases/amd64/amd64/ISO-IMAGES/13.1/FreeBSD-13.1-RELEASE-amd64-dvd1.iso.xz
unxz FreeBSD-13.1-RELEASE-amd64-dvd1.iso.xz
mdconfig -a -t vnode -f FreeBSD-13.1-RELEASE-amd64-dvd1.iso
gdisk -l /dev/md1
mkdir /mnt/md1p2
mount -t msdosfs /dev/md1p2 /mnt/md1p2  # read-write
```


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## chessguy64 (Jun 7, 2022)

To OP: at some point you have to switch troubleshooting methods due to time constraints and focus less on why the issue is occurring on set hardware, and move to a more viable solution. Since you're using multiple live CDs/DVDs, using something like this will solve all your problems -> https://www.ventoy.net/en/index.html

If you keep thinking about why you're so hungry instead of eating something, you will starve to death.


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## msplsh (Jun 7, 2022)

Did you compare the checksum on your image?

`openssl dgst -sha256 iso_image_file.iso`


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