Originally Posted by jakibaki

The workaround would have been booting into recovery and moving the blobs to the special partition from there (the partition is only read-only in fastboot mode) but since you're already on a new firmware you very likely won't need that.



Download and extract the .img file from here, enter fastboot mode and then cd to the folder where you downloaded that image and run

Code:

sudo fastboot flash oem SW_binaries_for_Xperia_AOSP_M_MR1_3.10_v13_loire.img

If it runs without an error that means that the partition is properly writable.