Yeah, the issue is that they build new linux kernel with 4k page size instead 64k before or other way round There are lots of discussions here http://community.wd.com/t5/WD-My-Cloud/New-FW-4-00-00-upgrade-results/td-p/761154/highlight/true/page/3 So btsync needs to be recompiled with that new non-standard kernel. but because btsync is closed-source software community can't do this by themselves. I just bought my wd own cloud and it is already have firmware version 4 so I'm trying to downgrade at the moment unfortunately downgrade hasn't worked for me. will have to restore rootfs with firmware version 4 one more update cloud restored version 4 by itself after failed boot from the second RAID partition so looking forward to seeing recompiled version for this non-standard kernel WD released. Seems like they put sticks into wheels on purpose by releasing version 4 with non-standard kernel Hi Roman Please have a look at this source code package from WD http://support.wdc.com/product/download.asp?groupid=904&sid=233〈=en you can find out linux arm compilers inside, both for firmware version 3 and version