Forgive me if somebody else asked/answered this, ( TOPIC search UEFI: 60+, incl text, a lot more!)
Setting up even 1 USB (DL, format, install, try boot) takes time, so to do many is many times x.
-->> How to tell if puppy ISO is BIOS or UEFI boot?!?
(most say nothing in feature section!)
if ISO name incl "...UEFI...ISO" does that mean UEFI ONLY? Both?
Example:
https://ftp.nluug.nl/ftp/pub/os/Linux/d ... 64-8.0.htm
Bionicpup64 Puppy 8.0----have tried BOTH 32 & 64, neither will boot.
(both have ...UEFI... in ISO name)
"Xenialpup64 7.5----notes indicate:
.....
Features include:
Kernel 4.9.58.
Ability to boot on both BIOS and UEFI enabled computers. "
2nd Q:
---->>> but NO LINKS! (how do I find/DL older versions?)
==============================
Read elsewhere:
"Unfortunately, the predominant attitude in the Puppy forum has long been "I hate Microsoft. I hate Windows. I hate UEFI. I hate Secure Boot. I hate GRUB2", which has hindered progress. Many forum members still consider BIOS+MBR+Grub4Dos to be the Puppy standard."
[LOL!]
Personally, I *LOVED* Win XP (made by MS)
BUT, I got a win 10 computer, had all kinds of problems (they don't come w manuals anymore!) *AND*, spent HOURS & HOURS trying to figure out how to BACK UP the bloody thing! (essential, when you start having problems; Reinstalled 98/XP many times) (oh, ya, they don't come w DISKS (USB?) anymore either! (GREEDY companies!))
NOW, "win 10 " computer sits UNUSED. (I talked to someone, they told me to go to LIBRARY, that didn't help either!) (win 10 computer HARDWARE, is FINE! [oh, GO ONLNE they say---but what if you CAN't?!? ) (MORE & MORE "help" is "OL ONLY" [UGH] )
[besides, *TONS* of bad/outdated/horrible advice OL, even about Linux!]
Actually, not really Linux fan either (sorry) *BUT*, can't use XP anymore, 
SO... limited options.
1 thing GOOD about Linux: Worst case: Go to another comp (or Lib) DL (USB now better than CD!) & REINSTALL! (ya, TRY THAT WITH WIN 10!!! [11? what's newest?])
UEFI-Secure boot: Same thing, right? [this *NEVER* ever used to be an issue!]
If you:
-have major problems, need to do a sys restore. (NO, not "system restore point" but the whole bloody thing!) [on average, 1-4x, over (yikes!) past 20+ years?]
then BOTH UEFI/"SECURE BS" can be bad! (OMG, reinstalled, but now won't boot!)
-DL X* utility, but won't boot either
-etc (many more); Last install, NO UEFI (mostly a NIGHTMARE, which is why so many hate it, WAY WAY more problems than it's worth!
[no such thing as "secure boot" anyway---if someone has PHYSICAL ACCESS to your computer (includes most PHONES) sooner or later they can get access to your data.]
[end rant]
https://www.gnu.org/software/grub/manual/grub/grub.html
I still have a *LOT* to learn about Grub2 (would encourage everybody---unless you're an EXPERT to read more & learn more!) *BUT* forget UEFI... Suppose you have:
EXT4 [now been around for how many years?] --->>> Which BTW, is if install almost ANY modern Linux, is the DEFAULT format. (I had to stop using some things, b/c they worked EXT3, *BUT*, *NOT*, w EXT4.)
1st ("p1) partition, is Ext4. (read a bunch of places now how this causes problems for some things)
*** MAKE NO MISTAKE, CHANGE IS HARD FOR PEOPLE ***
But, learning is almost always GOOD.
Grub2 is more complicated than GRUB. (almost it's own PROGRAMMING language! lol!)
Here's 2 hints found helpful:
1) Found out which sys you're using. (if you have old "GRUB", find a computer that has or you can put GRUB2 on.)
2) EXAMPLES. (even here, there's many good ones! )
"custom.cfg" (1 file used by GRUB2, several examples on here, used to load/start puppies)
[do a search]
also, " /etc/grub.d/40_custom" [contact me if you want a working example]
--->> You can use GRUB2, to load/boot "ISO files---including PUPPY. (no need to install!)
oK, my sys no UEFI (UGH!) so, can't give u example of that.
====================================================
Example "40_custom file" (you'll need sudo/ROOT permission)
( # ---means everything after than (1 line only) is comment)
"
#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
menuentry "fossapup64" {
insmod ext2
set isofile="/fossapup64-9.5-less-5.iso"
loopback loop (hd0,7)$isofile
linux (loop)/vmlinuz iso-scan/filename=$isofile
initrd (loop)/initrd.gz
}
# 1 of very few working "puppies"
==========================================================
(i'm guessing all/MOST? of issues w boot, are UEFI???? [check above, how to tell from ISO?])
Hope that helps somebody w NON-UEFI sys. [and GRUB2]
(sorry longer than planned combined several things)
I also have a very old Dell 5150 with Pentium D that boots bookwormpup