I have the same problem. Bought an adata pro sp900 128gb ssd and tried to clone the eMMC. Failed to make it boot from SSD but also managed to crash the original version of windows from eMMC when some updates failed to install.
Anyway, just wanted to use the SSD as a second storage unit but, after installing windows 10 from microsoft site and, using the drivers from the download section (many thanks to the user that made those available for us), now my SSD acts very strange: I get good speed when copying large files to it, but i get very low to 0 bytes speed when trying to copy that large file (video) from the SSD back to eMMC or to an USB flash drive (tried 2 drives – 1 was usb 3.0 and another one was 2.0). Also when trying to run the video from the SSD, the video player freezes.
I’m thinking the issue is with ahci/sata driver but I’m not sure about this.
Do you have any idea/solution?
Thanks.