I also reproduced it by chance with a SD card configured with an ARM bootloader located in block 2+. Changing one byte in block #6 restored the normal behaviour, where all partitions are correctly detected.
The issue did not exist in Trusty, it was added in the initial kernel configuration for Utopic and still exists in Vivid.
The issue has also been seen in http:// askubuntu. com/questions/ 638291/ unable- to-mount- external- usb-ssd
I also reproduced it by chance with a SD card configured with an ARM bootloader located in block 2+. Changing one byte in block #6 restored the normal behaviour, where all partitions are correctly detected.
The issue did not exist in Trusty, it was added in the initial kernel configuration for Utopic and still exists in Vivid.