Olimex JTAG-AVR upgrade problem

Hello,

I have two Olimex AVR-JTAGs. but I can’t get one of them to work anymore with AVR Studio after AVR-Studio tried to update the firmware.

I have seen that firmware upgrade Instruction on http://www.olimex.com/dev/avr-jtag-upgrade.html

but I don’t have a AVR-PG1B and no PonyProg.

Question:

Instead isn’t it possible to enable the internal bootloader of the Olimex JTAG-AVR with an STK500? And if YES what is the precedure?

Thank you.