I have used the method in the following url to create a trisquel-modified.iso.
I wrote trisquel-modified.iso in a cdrom and it boots fine without any problems.
Then I used my usb stick and did the following. (The usb stick was having one FAT32 partition).
dd if=trisquel-modified.iso of=/dev/sdb1
It wrote the contents of trisquel-modified.iso to sdb1. Then I tried booting from the usb stick, but it never boot. It is just showing the screen "Loading the Operating System..." and it stays there.
Please help me to know, what is wrong here. My intention is to boot trisquel-modified.iso from a usb stick that is having iso9660 filesystem.
I have also tried the following, but now the usb stick is not getting detected.
dd if=trisquel-modified.iso of=/dev/sdb