After an upgrade to 7.0.3, there is see no bootable partition. The partition is shown as unknown. This article provides a resolution to this error.
This can be caused by an upgrade onto the next partition failing, and then somehow rebooting into that partition. This is booted in an invalid image, hence it shows no bootable partition.
E.g., If an upgrade failed due to the space issue, and the device rebooted back into the lower version, sometimes, a user will then switch to boot into the upgraded partition manually because he can see the image on the partition.
If you find Exinda in this state, you should boot back into the valid partition. Once you are back in the valid partition, you can try an upgrade to version 7.4.