I am now the Happy owner of a TT-730 with NC 9.845 with Map 895.4438 and all WORKS !! BUT

I Still have the older bootloader 5.5015. Actually is was quite simple with all the generously provided tools here !!

How do I update the bootloader to a newer version? Obviously it's not as critical as the iphone bootloader which I have upgraded/downgraded, but how to do it?