After installing mSATA disk on UniElec U7623-06 board the device does not show up on the device list (ls /dev/sd*) (I have also checked ls /dev/*). There is also no information about disk discovery in kernel log (dmesg).
Installing kmod-ata-ahci package have not changed anything.
Is mSATA supported in OpenWRT for UniElec U7623-06 ??
mSATA is SATA, there's afaik no difference except for the format/connector.
you're probably still missing modules.
lspci (-v) and dmesg would help you identify the missing parts.
if you figure it out, update https://openwrt.org/toh/unielec/u7623
Seems its the Asmedia ASM1061 controller, try "reading" - it's in polish 
Ah, we forgot to enable the first PCIe controller. I fixed it now that someone pointed it out to me... and then I found this forum post.