There is no means to get s-off with hboot 1.5. If you want to root and ROM with hboot 1.5 you have to use the HTC unlock method. This method does not give you s-off, which creates issues with accessing the kernel partion. In order to flash a different kernel or a ROM with a different kernel, you need to extract the kernel from the ROM or download the kernel seperately and flash it using fastboot and the adb or fastboot commands. I don't know them off the top of my head, but if you search hard enough you will find them. Otherwise, you can also downalod the Flash Image GUI app for $.99 from the market and flash kernels from the app. When I was on hboot 1.5 this was how I did it and it is by far the easiest way to flash a kernel or new recovery image. I recently had my phone replaced under warranty and got it with hboot 1.4 still loaded, so I no longer have this problem. But, if you are running hboot 1.5 and you want to a new ROM or kernel, Flash Image GUI is the way to go!