Grub2 has allowed booting directly from an iso file for years. There are a number of sites with detailed explanation on doing it including the one to the Ubuntu site below which is a little more detailed and also has some sample menuentries.

https://help.ubuntu.com/community/Gr...ooting_the_ISO

You need persistence for a 'Live' system and the method used varies with distribution. The link below explains the process for Debian. Don't use Debian myself so don't know how well it works.

https://www.linux.com/blog/creating-...non-techies%20

I found an option on the Debian installer option on a Debian "dd" to another USB which I can install GRUB on the pendrive andwhich I can specify the MBR of the pendrive to be written. I tryied it and worked very good. It gave me what I wanted: the simplier GRUB menu. But, as always, it wasn't as beautifull as it look. IF I try to boot the Debian it loads many modules until when it asks me to login, before the graphical system to be load. I searched internet and find the only user by default on Debian live is "user:live" which says to me it's incorrect, so can't be load.

Any clue about that?

TOday I don't have time to try things some of you pointed to me, but tomorrow I will try to manually install GRUB2 and do the persistance.

Thanks

You might post a link to what you used or give more details on exactly what you were instructed to do. That way, Debian users might have some suggestions for you although I'm not really sure what the problem is in this case.

That was my experience also the last time I used Debian. Did you want or try to create another user during your install?

Finally, what I did is go to windows and install Yumi, because all that days and troubles to install grub with all the OS´s working is really too much. I love Linux, but can´t understand why there is an aplication to do all that stuff informing you of all the problems found (if there is some) and a suggestion on how to fix it. So sad to see in 2019 Linux with all that basic functions forcing you to spend a whole week to try to get through, and finally having to go to windows because don´t want to waste more of your time.

And since Yumi is using SSyslinux and not Grub to boot, I have to install Rufus (or grub, but we saw this is not possible) to be able to get the persistence of the Debian-live, because the guide provided here is from 2011, and it no longer works. If someone needs it, this is the correct process to make Debian persistent: http://www.fabbnet.net/Live_Persistent.htm

Thansk to all for the time and the effort

I tried YUMI again the other day and was not satisfied. I found AIO Boot to be very nice.
I made a 15GB Fat32 partition on my 64GB USB key with diskpart in Windows, then the rest of the key a NTFS partition. Hit the AIO executable, ensure the USB key is in the "desired drive" drop down menu and leave the check in "auto install bootloader", then hit the "Get 7z file" button to unpack it into the Fat32 partition of the USB key. Then Go into the Fat partition of the key and click on AIOCreator.exe and select "Integrate" to set up ISOs.

For Ubuntu Fedora Gparted Live and Linux Mint, it said these distributions support persistence, do you want to make a persistence file? with a variety of sizes of the persistence file to choose from, so I selected 3GB for each, after it was done and said "Happy booting", I integrated Fedora 29 with persistence, Win10 PE SE, Win8.1 PE SE, BootitBM and a few more bootable ISOs.

It uses Grub2 Legassy and I can Boot the Linux OSs in both UEFI and BIOS mode, the persistence works with Ubuntu and Mint and Gparted Live, but not Fedora. It boots everything I put in there in what ever mode it supports, it also has 3 other boot loaders for MacOSX, FreeDOS and a bunch of others, it can boot multiple partitions on the Key, etc. etc. etc.

And every OS can access the Data in the NTFS partition.

IT'S AMAZING!!!!

BTW:
I didn't have to make 2 partitions with what I put on the key, I could of just had one NTFS partition which would allow larger than 4GB persistence file. With AIO, you can partition the key GPT if you want, you can install operating systems native instead of live if you want and avoid persistence, it'll boot everything in whatever mode you choose from whatever partition it's in. I think I'm gonna install Fedora native since it's an A..hole with persistence, need to disable auto update with Fedora or it'll blow up the key quickly with persistence.

EDIT: Ops! Apparently I did need the Fat32 partition.

Of course it is possible to install Grub to a usb/flash drive. You just can't do it on a read-only filesystem and I thought you understood that from your earlier posts. Best way to do this and have multiple iso files or Live systems to boot is with one partition with Grub boot files. This requires manually creating the grub.cfg file for each entry but that only requires the ability to read and write (type). There are countless web sites with templates/examples of grub.cfg entries to use. In any case, glad multiboot worked for you.