#Try 1
#recipe
SRC_URI:mx8m-generic-bsp ?= "extrepo"
SRC_URI:mx8m-generic-bsp += "patch1"
SRC_URI:mx8m-generic-bsp += "patch2"

#local.conf
SRC_URI:pn-fb5-uem := "localrepo "

#result
SRC_URI = "extrepo patch1 patch2"


#Try2 with chained local
#local.conf
SRC_URI:mx8m-generic-bsp:pn-fb5-uem = "localrepo "

#result
SRC_URI = "localrepo"