Changing the default item in the Linux installer?

Question

linux

Do not ask: "Why, fool?" too long to explain. When the machine starts up from a flash drive with a distro (in my case, parrot security os on Debian), a menu pops up with a choice of actions (boot into a live cd, such an installation, such an installation, etc.) and a timer (at the end of the time, a certain item if no key was pressed). I need this timer to be not on a live cd, as in almost all distros, but on a different point. Do not write about Klava, which I can use, I just need the timer to be in a different place. If this is at all possible to implement, then please let me know. Thank you for your attention!

Answer 1

I need this timer to be not on a live cd, as in almost all distros, but on a different point.
If this is at all possible, please let me know.

Maybe. The bootloader configuration is located on the liveCD in the file /isolinux/live.cfg, you can see it like this:

$ mkdir cd
$ sudo mount -o loop Parrot-security-4.3_amd64.iso cd
mount: /dev/loop0 is write-protected, mounting read-only
$ head -n3 cd/isolinux/live.cfg
label ^live
        menu label ^Live Mode
        menu default

This menu default needs to be moved to another location.
How to do it? The easiest way is to edit iso with a hex editor. In a freshly downloaded 64-bit parrot security os iso, this line is located at 0x546e024, it is searched for with a simple grep:

$ hexdump -Cv Parrot-security-4.3_amd64.iso | grep -A3 'label ^live'
0546e000  6c 61 62 65 6c 20 5e 6c  69 76 65 0a 09 6d 65 6e  |label ^live..men|
0546e010  75 20 6c 61 62 65 6c 20  5e 4c 69 76 65 20 4d 6f  |u label ^Live Mo|
0546e020  64 65 0a 09 6d 65 6e 75  20 64 65 66 61 75 6c 74  |de..menu default|
0546e030  0a 09 6c 69 6e 75 78 20  2f 6c 69 76 65 2f 76 6d  |..linux /live/vm|

For example, I made the second item the default item:

0546e000  6c 61 62 65 6c 20 5e 6c  69 76 65 0a 09 6d 65 6e  |label ^live..men|
0546e010  75 20 6c 61 62 65 6c 20  5e 4c 69 76 65 20 4d 6f  |u label ^Live Mo|
0546e020  64 65 0a 09 6c 69 6e 75  78 20 2f 6c 69 76 65 2f  |de..linux /live/|
0546e030  76 6d 6c 69 6e 75 7a 0a  0a 69 6e 69 74 72 64 20  |vmlinuz..initrd |
0546e040  2f 6c 69 76 65 2f 69 6e  69 74 72 64 2e 69 6d 67  |/live/initrd.img|
0546e050  0a 0a 61 70 70 65 6e 64  20 62 6f 6f 74 3d 6c 69  |..append boot=li|
0546e060  76 65 20 68 6f 73 74 6e  61 6d 65 3d 70 61 72 72  |ve hostname=parr|
0546e070  6f 74 20 6c 6f 63 61 6c  65 73 3d 65 6e 5f 55 53  |ot locales=en_US|
0546e080  2e 55 54 46 2d 38 20 6b  65 79 62 6f 61 72 64 2d  |.UTF-8 keyboard-|
0546e090  6c 61 79 6f 75 74 73 3d  75 73 20 71 75 69 65 74  |layouts=us quiet|
0546e0a0  20 73 70 6c 61 73 68 20  61 70 70 61 72 6d 6f 72  | splash apparmor|
0546e0b0  3d 30 0a 09 0a 6c 61 62  65 6c 20 74 65 78 74 0a  |=0...label text.|
0546e0c0  0a 6d 65 6e 75 20 6c 61  62 65 6c 20 54 65 72 6d  |.menu label Term|
0546e0d0  69 6e 61 6c 20 6d 6f 64  65 0a 0a 6d 65 6e 75 20  |inal mode..menu |
0546e0e0  64 65 66 61 75 6c 74 0a  09 6c 69 6e 75 78 20 2f  |default..linux /|