I’ve been compiling packages not in the standard sources by downloading the SDK for the openwrt (hopefully vmuirt64 should be the same) changing the sources in the SDK to the generic openwrt ones and downloading and compiling the package.
Not sure if it’s recommended, but here’s what I do.
Choose the version from
Select your version, then images and the SDK should be there.
Edit feeds.conf.default (may need to adjust if it’s a different version then 21.02 )
src-git base https://git.openwrt.org/openwrt/openwrt.git;openwrt-21.02
src-git packages https://git.openwrt.org/feed/packages.git;openwrt-21.02
src-git luci https://git.openwrt.org/project/luci.git;openwrt-21.02
src-git routing https://git.openwrt.org/feed/routing.git;openwrt-21.02
src-git telephony https://git.openwrt.org/feed/telephony.git;openwrt-21.02
Update new feeds
./scripts/feeds update -a
Download package for qrencode
./scripts/feeds install qrencode
You may have to confirm the build operation in menuconfig, but just select save and quit.
Go to the bin directory or just search for make qrencode* and libqrencode* secure copy (scp) to the device and install using opkg.