[SOLVED] Trying to make a iso from and original need to know how to see the boot bytes.

bscho · 03-01-2020, 05:16 PM

I am using Imgburn to take the folders from an iso but the byte count is lower than the bytes if I just make the iso from the original disc.

I use the isolinux.bin as the boot image Which appears to work but fails after a few minutes with initrfs

I see their is a difference in the count of about 200,000 bytes

Can I read the iso and see the boot image part?

Maybe someone knows am I using the wrong boot image.

rtmistler · 03-02-2020, 09:47 AM

Quote:

Originally Posted by bscho

I am using Imgburn to take the folders from an iso but the byte count is lower than the bytes if I just make the iso from the original disc.

I use the isolinux.bin as the boot image Which appears to work but fails after a few minutes with initrfs

I see their is a difference in the count of about 200,000 bytes

Can I read the iso and see the boot image part?

Maybe someone knows am I using the wrong boot image.

Well .... What are you trying to do?

If you just wish to make a boot capable copy of an ISO file, and the original works, then "various clone methods", my favorite being just dd.

elucches · 03-02-2020, 06:14 PM

You can mount the iso using the loop option.
For example:

Code:

mount -o loop -t iso9660 debian-live-10.2.0-i386-standard.iso /media/iso

aus9 · 03-02-2020, 08:48 PM

boot bytes are not meant to be read.....but you can kind of see them like this
top section is raw
bottom section made human readable

Code:

sudo su
dd if=android-x86_64-9.0-rc2.iso  bs=512 count=1
3퐐����������������������������3���ռ|��f1�f1�fSfQW�ݎ�R�|����KR�A��U1�0���r��U�u��t
                                                                                  f���B��ZQ���?[Q��@P��SRP�|�f���D��f@����f�>@|��xpu	���{�D|�isolinux.bin missing or corrupt.
f`f1�f�{f�{fRfPSjj��f�6�{����Œ�6�{��A���{��dfa��Operating system load error.
^���>b��<
u������ �g	�?���U�1+0 records in
1+0 records out
512 bytes copied, 0.00339301 s, 151 kB/s


#### bottom section
dd if=android-x86_64-9.0-rc2.iso  bs=512 count=1 | strings
1+0 records in
1+0 records out
512 bytes copied, 7.9073e-05 s, 6.5 MB/s
fSfQ
xpu	
isolinux.bin missing or corrupt.
f`f1
{fRfP
Operating system load error.

quite a few distros use isolinux (syslinux on hd)

fatmac · 03-03-2020, 04:33 AM

Check these out.

https://wiki.osdev.org/El-Torito

https://wiki.osdev.org/Mkisofs

https://serverfault.com/questions/89...om-a-directory

bscho · 03-03-2020, 06:21 AM

Quote:

Originally Posted by elucches

You can mount the iso using the loop option.
For example:

Code:

mount -o loop -t iso9660 debian-live-10.2.0-i386-standard.iso /media/iso

I have done that but it is read only. How do I make it writable

bscho · 03-03-2020, 06:28 AM

Quote:

Originally Posted by aus9

boot bytes are not meant to be read.....but you can kind of see them like this
top section is raw
bottom section made human readable

Code:

sudo su
dd if=android-x86_64-9.0-rc2.iso  bs=512 count=1
3퐐����������������������������3���ռ|��f1�f1�fSfQW�ݎ�R�|����KR�A��U1�0���r��U�u��t
                                                                                  f���B��ZQ���?[Q��@P��SRP�|�f���D��f@����f�>@|��xpu	���{�D|�isolinux.bin missing or corrupt.
f`f1�f�{f�{fRfPSjj��f�6�{����Œ�6�{��A���{��dfa��Operating system load error.
^���>b��<
u������ �g	�?���U�1+0 records in
1+0 records out
512 bytes copied, 0.00339301 s, 151 kB/s


#### bottom section
dd if=android-x86_64-9.0-rc2.iso  bs=512 count=1 | strings
1+0 records in
1+0 records out
512 bytes copied, 7.9073e-05 s, 6.5 MB/s
fSfQ
xpu	
isolinux.bin missing or corrupt.
f`f1
{fRfP
Operating system load error.

quite a few distros use isolinux (syslinux on hd)

Have done that but no output
where do you see it?

ondoho · 03-03-2020, 02:39 PM

Quote:

Originally Posted by bscho

I have done that but it is read only. How do I make it writable

You don't. iso9660 is read-only.

teckk · 03-03-2020, 04:13 PM

Copy everything to a different directory, then make changes, make new iso. Best way, you keep the original.

Or to edit in place look at man losetup. If you mess it up you will destroy your iso.

aus9 · 03-03-2020, 07:02 PM

Quote:

Have done that but no output
where do you see it?

I changed dir to where my iso images are.

If you open a terminal, you are currently at /home/yourname

generically you could try but put actual pathway name in.

sudo dd if=/pathway2/<nameofiso>.iso bs=512 count=1 | strings

bscho · 03-05-2020, 07:51 AM

Quote:

Originally Posted by fatmac

Check these out.

https://wiki.osdev.org/El-Torito

Hi thanks for that I am stuck though with this

Especially make the boot image for PC-BIOS available at path ./prepared_for_iso/boot/loader.sys , so that it will appear in the ISO filesystem as /boot/loader.sys .

I have done this in the terminal but it objects with the boot/loader.sys part

mkisofs -R -J -c boot/bootcat -b boot/loader.sys -no-emul-boot -boot-load-size 4 -o ./bootable.iso ./prepared_for_iso

I have done the ./prepared_for_iso and put all the folders and files in that. But cannot figure out the /boot/loader.sys part

Have you any idea?

Thanks

fatmac · 03-05-2020, 08:49 AM

You need to have syslinux installed on your system.

https://wiki.syslinux.org/wiki/index...slinux_Project
https://wiki.syslinux.org/wiki/index.php?title=Download
https://wiki.syslinux.org/wiki/index.php?title=HowTos

(Seems like UEFI has made them change a few things since I last created a bootable CD.)

bscho · 03-06-2020, 01:42 AM

Quote:

Originally Posted by fatmac

You need to have syslinux installed on your system.

https://wiki.syslinux.org/wiki/index...slinux_Project
https://wiki.syslinux.org/wiki/index.php?title=Download
https://wiki.syslinux.org/wiki/index.php?title=HowTos

(Seems like UEFI has made them change a few things since I last created a bootable CD.)

I have done it with this way as well and it still does not work. I have done it with two distros and they both run to a point where it stops at initramfs
This is the same as when I used Imgburn to make the iso up.

I also found that I was supposed to put an image in and it I did not it would not run as it wanted tools.imz I made a img and renamed it to tools.imz and this allowed it to work but only to stop with initramfs again.

This is a big puzzle any ideas please.

elucches · 03-06-2020, 05:47 PM

There's also https://wiki.archlinux.org/index.php/Syslinux.

bscho · 03-06-2020, 10:17 PM

Quote:

Originally Posted by elucches

There's also https://wiki.archlinux.org/index.php/Syslinux.

Thanks have sorted the problem. The issue was a hidden file .disk which when put through syslinux was changed to _disk

This is now solved.