I have purchased 546WP board (The full model number is 546WP 6B12A).
Is it possible to upgrade the bootloader ? and does it support openWRT ?
For the WP546 board, it is a rather old model. When did you purchase it?
I wouldn't advise upgrading the bootloader. If it's not done correctly, the board may become unusable. Therefore it's only done at the production side.
Are you asking how to upgrade the firmware? Here are the instructions:
This is what you want if you're trying OpenWRT.
There's an OpenWRT writeup here you could read through:
You would also like to try the latest wireless embedded boards:
There's also LEDE development on WPJ342, WPJ344, WPJ531, WPJ558:
The instructions for uploading the loader are here:
CompexWRT Loader Upgrade.
Did you do it this way?
The files that you need are here:
We are still trying to find a suitable Windows XP computer to test this. As the required software only runs on Windows XP, JTAG is hardly being used now. Based on your screenshots, I would hazard a guess that the problem could lie in the parallel port or JTAG cable connection. You can't use a USB to parallel port converter.