Installed haiku, now can't boot from usb

just installed the latest nightly of haiku on a spare partition, just to check it out. now when i try to boot a linux install from usb, nothing happens, from cd, works fine.
i used the haiku bootloader, and also used the second option in the ‘tools’ (can’t remember what it’s called), maybe that stuffed something up?

i still have usb checked in the bios as the first boot option

any ideas?

computer: hp pavilion g6

…I believe that you have to check your bios’ boot list…

sorry, should have said that, yes i have checked it, boot from usb stick is still at the top of the list.
the only thing that’s changed is I installed haiku, and used its bootmanager, and also selected the 2nd option from the tools menu (can’t remember the name, something about writing haiku to something, seemed like a good idea at the time)
the usb stick has a xubuntu iso instaled via unetbootin, also writing the haiku anyboot image to usb stick gives the same results (copmputer completely ignores it, and goes to the boot menu)

pretty sure it won’t be the haiku and xubuntu images at fault, as these were booting fine before i installed haiku.

Maybe you chose to write haiku bootmanager to the mbr. If I’m right, this would tell haiku to boot off the usb instead of whatever was supposed to before. Hopefully this helps.

yes, i wrote it to the mbr. i was sure that was the standard thing to do?

what would be a fix for it? (i’ve installed xubuntu since then which has overwritten with grub)