user@ubuntu:/automnt/ssd/AGL_HomeScreen/build-rpi3$ bitbake  agl-demo-platform
Loading cache: 100% |#########################################################################################| Time: 0:00:03
Loaded 2886 entries from dependency cache.
Parsing recipes: 100% |#######################################################################################| Time: 0:00:07
Parsing of 2173 .bb files complete (2152 cached, 21 parsed). 2908 targets, 371 skipped, 0 masked, 0 errors.
NOTE: Resolving any missing task queue dependencies
ERROR: Nothing RPROVIDES 'linux-firmware-brcm43430' (but /automnt/ssd/AGL_HomeScreen/meta-agl-demo/recipes-platform/images/agl-demo-platform.bb RDEPENDS on or otherwise requires it)
NOTE: Runtime target 'linux-firmware-brcm43430' is unbuildable, removing...
Missing or unbuildable dependency chain was: ['linux-firmware-brcm43430']
ERROR: Required build target 'agl-demo-platform' has no buildable providers.
Missing or unbuildable dependency chain was: ['agl-demo-platform', 'linux-firmware-brcm43430']

Summary: There were 2 ERROR messages shown, returning a non-zero exit code.