I have used the Update Tool in the latest WinCE6 image 1.5 to update the bootloader and after that the module was unbootable.
Could you please completely erase the flash and reprogram the latest image as per our documentation:
Please use the latest updateTool which is coming with release image, please don’t use OS inbuilt / running update tool. We are always recommending to use newest update tool which will be in the release package.
Let us know if you are facing the issue after above procedure.