This is about making the USB flash drive install of Puppy, boot in the proper pupmode, for running Puppy from a USB flash drive.
On the USB flash drive will be a boot config file.
The file should be one of these:
isolinux.cfg
OR
syslinux.cfg
If Grub4dos bootloader is on the USB flash drive and used to boot it.
menu.lst is used.
In Rox file manager navigate to the file you have.
Left click on it to open it in a text editor.
Example:
isolinux.cfg
default puppy
display boot.msg
prompt 1
timeout 50
F1 boot.msg
F2 help.msg
F3 help2.msg
label puppy
kernel vmlinuz
append initrd=initrd.gz pmedia=cd
Change pmedia=cd to pmedia=usbflash.
That tells the Puppy boot process that it is on a USB flash drive and to operate for running from a USB flash drive.
If Puppy is installed by using the Puppy Universal Installer.
The installer would have made this change based on what you installed Puppy on.