Bulding custom firmware - cannot satisfy the following dependencies for kmods

I tried to build an OpenWRT firmware for a mvebu (linksys wrt32x). At the end of the build process, the make package/install spits out some error messages as shown below. I wonder if anyone out here has encountered this issue and can provide an answer with a solution to fix this issue.

Configuring kmod-crypto-crc32Collected errors:
 * satisfy_dependencies_for: Cannot satisfy the following dependencies for kmod-bluetooth_6lowpan:
 *      kmod-6lowpan
 * opkg_install_cmd: Cannot install package kmod-bluetooth_6lowpan.
 * satisfy_dependencies_for: Cannot satisfy the following dependencies for kmod-mwifiex-sdio:
 *      iw
 * opkg_install_cmd: Cannot install package kmod-mwifiex-sdio.
.
Configuring kmod-fs-f2fs.
Configuring ip6tables.
Configuring libexpat.
Configuring kmod-fs-squashfs.
Configuring kmod-ipt-offload.
Configuring ppp-mod-pppoe.
make[1]: *** [package/Makefile:68: package/install] Error 255
make[1]: Leaving directory '/home/serg/openwrt'
make: *** [/home/serg/openwrt/include/toplevel.mk:218: package/install] Error 2

Thanks!

master or 18.06.x?

latest master with CONFIG_ALL_KMODS=y