do not try to load uf2 file if target does not support it
do not try to load uf2 file if target does not support it

switchinnovations/pxt,playi/pxt,switch-education/pxt,Microsoft/pxt,Microsoft/pxt,playi/pxt,switch-education/pxt,switch-education/pxt,Microsoft/pxt,switch-education/pxt,Microsoft/pxt,switchinnovations/pxt,playi/pxt,switch-education/pxt,playi/pxt,Microsoft/pxt,switchinnovations/pxt,switchinnovations/pxt