【Solved】persistence no prompt

[bertus65]

Hello,
I like Ventoy very much, but now I have a problem with persistence.
Now I want to use a live ubuntu20.4desktop with persistence.
What I've done so far: 

• searching on this forum for a solution
  
• ventoy 1.064, tested with uefi and legacy boot
  
• No prompt menu displayed? (prompt for select boot with or without persistence)?
  
• http://json.parser.online.fr OK
  
• During Ventoy Boot pressing <f5> check persistence plugin configuration shows Image=ok, Backend=ok, Dump Persistence=succes
  
• in grub vt_dump_persistence same result as previous step
  
• label persistence file casper-rw (I read in https://askubuntu.com/questions/1297758 since ubuntu version 20 this should be writable,
  but I think this is not causing my problem "no prompt menu" 
  

Can someone help me to fix my problem?
Best Regards Bart

[Steve2926]

You just add the persistence file and then add an entry into the ventoy.json file
https://ventoy.net/en/plugin_persistence.html

[bertus65]

You just add the persistence file and then add an entry into the ventoy.json file
https://ventoy.net/en/plugin_persistence.html

Hello,
That's what I've done and tested.

My content ventoy\ventoy.json
{
"persistence": [
{
"image": "/ISO/ubuntu-21.04-desktop-amd64.iso",
"backend": "/persistence/persistence_ext4_512MB_casper-rw.dat"
},
{
"image": "/ISO/ubuntu-21.04-desktop-amd64.iso",
"backend": "/persistence/persistence_ext4_512MB_writable.dat"
}

]
}

[Steve2926]

when you select the ISO in Ventoy menu, you should be prompted to boot without persistence or using the persistence.dat file.
If you don't get that prompt then you have done something wrong in the ventoy.json file.

---

Maybe you extracted the wrong persistence file?
Unless you tell us exactly what you have done, it is difficult to help but if you dont get a Ventoy prompt then you paths are probably wrong in ventoy.json file.

[bertus65]

when you select the ISO in Ventoy menu, you should be prompted to boot without persistence or using the persistence.dat file.
If you don't get that prompt then you have done something wrong in the ventoy.json file.

---

Maybe you extracted the wrong persistence file?
Unless you tell us exactly what you have done, it is difficult to help but if you dont get a Ventoy prompt then you paths are probably wrong in ventoy.json file.

Hello,
Sorry, forgot to mention how I obtained and tested the persistence file.

I downloaded and extracted the persistence file from https://github.com/ventoy/backend/releases 
(extracted persistence_ext4_512MB_casper-rw.dat and opened this file in UbuntuLive with Gparted
I can see It is ext4 and the label is casper-rw which is the right one for ubuntu.

Syntax ventoy.json is ok, checked this in several manners.
So I checked everything and everything seems OK.
Only problem, no prompt asking which persistence to choose  when booting ventoy usb

[longpanda]

Press c to enter grub shell and run vtdebug on then press ESC to return and then select the ISO file to boot.
Check the debug message or take some photos.

[bertus65]

Press c to enter grub shell and run  vtdebug on  then press ESC to return and then select the ISO file to boot.
Check the debug message or take some photos.

---

Copied the persistence file persistence_ext4_512MB_casper-rw.dat with label casper-rw
to a new persistence file persistence_ext4_512MB_writable.dat with label writable
Didn't make a differenc, still no prompt

[longpanda]

Maybe case-sensitive problem.
Try change "image": "/ISO/ubuntu-21.04-desktop-amd64.iso"  to  "image": "/iso/ubuntu-21.04-desktop-amd64.iso",

Recommend to use VentoyPlugson to automatically generate ventoy.json to avoid problem.
https://www.ventoy.net/en/plugin_plugson.html

[bertus65]

Thanks! It's working now.
I noticed the only selectable persistance file is the one with the label writable for ubuntu 21.04.
I used http://json.parser.online.fr for syntax checking and this program didn't complain about upper/lower case.
But you are right, it's better to use the plugin_plugson to generate the ventoy.json.
Best regards Bart

[longpanda]

If you want to set more than one persistence dat files for one ISO file.

Code:

{
    "persistence":[
        {
            "image":"/iso/ubuntu-21.04-desktop-amd64.iso",
            "backend":[
                "/persistence/persistence_ext4_512MB_casper-rw.dat",
                "/persistence/persistence_ext4_512MB_writable.dat"
            ]
        }
    ]
}