Is this the error you are referring to
https://support.hp.com/au-en/document/ish_3053911-2842957-16
It seems it could be caused by a number of things… that HP document basically says fix everything. Not very helpful for diagnosis.
@davg did some tests which suggested his 3FO was not due to a faulty disk.
@gary might be right here.
If the Mint installer made a mess of setting up the disk, eg wrote grub in the wrong place, it would fail to boot.
Two options to try
The 3fo error comes from a hp error check about the disk, but not sure what triggers it and true or false that could be the root of the issue.
Disk checking may show why on the disk table
I think I would be running smartctl on that disk… just to be sure.
My guess is that it is an installer problem, but thst is only a guess.
What is the best thing we can get @davg to do to try and diagonose?
I think I would opt for try installing another distro. I think @davg could handle that.
I agree hence lmde
Perhaps disk checking first after boot
Either command line or using menu tool with screen shot to see what is going on
There have been issues with mint 22 but only read about them not seen any to comment on, something about the kernal in the last release. Lmde uses a older version i think
Last night, I tried to reinstall LMDE6 fully default, with the result that it doesn’t boot any longer, steady 3F0.
Thanks, we needed to try that.
That means my guess of an installer problem is probably wrong.
Could you try 2 things
I hope there is no secure boot involved? How old is this laptop? Has it run linux previously?
That HP support link says restore bios settings to default. That is a bit drastic, but we may be forced to try it.
Already tried everything you mentioned.
Meanwhile, I restored from an image backup, back to the previous situation that I can boot well, but reboot always throws that 3F0.
Thank you, that proves
There is only one possibility left
When you do grub-install ( or when the linux installer does it for you), two things happen
Now, it seems that in your case , the BIOS code is corrupted, and it is either not receiving the message, or not acting on it. So the disk does not get into the boot menu.
What can we do ? Four things in order of seriousness
Not a real joyful diagnosis I am afraid.
@abu
Are you running a separate /boot partition with the boot flag on /boot?
No. I don’t have a separate boot partition.
This is obviously the problem, according to some log entries I saw. Not nice, but I can live with it.
There is just one BIOS upgrade available at the HP sites. But I’m afraid this will not solve my issue.
@abu
I had a similar Dell laptop, but instead of taking the “Linux route” I left the W7 Home Premium installed. I then downloaded a W10 ISO and a W11 ISO, use 7z to extract both to separate folders and replaced the W10 installer with the W11 installer, mounted the hacked W10 ISO, from within W7 and have been running W11 ever since.
I get security updates but I do not do feature updates, and when W11 ceases to run, I will then retire the laptop.
I am with Neville on his replies.
Before all this started you were running a dual boot with ubuntu although a older version do you still have a copy we can try ?
Yes change bios battery
But try this first
https://support.hp.com/us-en/document/ish_3932413-2337994-16
Then your / partition will need the “boot flag”
Notice that @Daniel_Phillips has a boot flag on the /boot partition.
That is required for legacy boot
If you dont have a /boot partition, the boot flag should be on the / partition.
Check that you have that.
Legacy boot will not work without it.
Sorry I just noticed @Daniel_Phillips has posted the same comment
A bit old, but someone else had a 3f0 problem and a solution was posted.
Also on a HP machine.
That one seems to be a genuine failed disk.
3fo is hardly what I would call a user friendly error message.
Why cant we have it in English?
In our walk-in repair shop, people give us their old machines to renovate and pass on to those who need them.
Recently, I had problems getting LM21.3 then LM 22 to boot on 3 HP portables that are recent by our standards (less than about 8 years). I can’t say much because there may be faults that are hard to detect, but I’m getting too old to do all the geek stuff mentioned here.
To run my CNC workshop machine, I bought directly from Lenovo an entry-level Ideacentre dated 2020. It refused to install Ubuntu or Mint, and Lenovo replied that it wasn’t designed for Linux, despite the fact that in the past they have sold PCs with Linux.
I don’t want to sound paranoid, but I’m beginning to wonder whether some of this might form part of a subtle anti-FOSS strategy. The thought occurred to me when looking up one of the flagrant design faults in LibreOffice, which are fatal for many potential uses, and never get fixed. This is the latest in a chain of more than 20 related bug reports that started in 2012 or earlier:
https://bugs.documentfoundation.org/show_bug.cgi?id=46448
Thanks for the link, unfortunately it didn’t help either. At least I’ve learned a new word — finicky. 
I wonder if a total format of the hard disk and removal of all partitions so in effect it is a new disk would help. If the problem is within the bootable area of the disk this would either flag sectors not to use or clear errors
