The_Turtle

I experienced quite the similar struggle. In my case, I tried the Update from DSM 6.0.2 to 6.1.3 on HP Proliant Gen8 baremetal. But I couldn't bott from the image. The solution was to use the MBR loader version, because the HP seems not to support UEFI. Because the Size is quite the same as before, I assume the image file you are missing is now in somwhere else in the loader. I hope this helps, gibe the MBR loader a try.