The Full Debug Symbol (FDS) makefile logic is as follows (<os>/makefiles/defs.make):

 ifeq ($(BUILD_FLAVOR), product)
    FULL_DEBUG_SYMBOLS ?= 1
    ENABLE_FULL_DEBUG_SYMBOLS = $(FULL_DEBUG_SYMBOLS)
  else
    # debug variants always get Full Debug Symbols (if available)
    ENABLE_FULL_DEBUG_SYMBOLS = 1
  endif
  _JUNK_ := $(shell \
    echo >&2 "INFO: ENABLE_FULL_DEBUG_SYMBOLS=$(ENABLE_FULL_DEBUG_SYMBOLS)")
  # since objcopy is optional, we set ZIP_DEBUGINFO_FILES later

  ifeq ($(ENABLE_FULL_DEBUG_SYMBOLS),1)
   ...
  else
    OBJCOPY=
  endif

So if we have explicitly disabled FDS then OBJCOPY will be cleared by the above. However we then have:

  ifeq ($(OBJCOPY),)
    _JUNK_ := $(shell \
      echo >&2 "INFO: no objcopy cmd found so cannot create .debuginfo files.")
    ENABLE_FULL_DEBUG_SYMBOLS=0
    _JUNK_ := $(shell \
      echo >&2 "INFO: ENABLE_FULL_DEBUG_SYMBOLS=$(ENABLE_FULL_DEBUG_SYMBOLS)")

So we then erroneously (and noisily) report that OBJCOPY could not be found when in fact we never looked for it, and didn't need to.

The OBJCOPY logic should be folded into the preceding " ifeq ($(ENABLE_FULL_DEBUG_SYMBOLS),1)" block.