Merge remote-tracking branch 'nl6720/bootmodes-2'

* nl6720/bootmodes-2:
  mkarchiso: improve functions and comments
7 jobs for master in 32 minutes and 32 seconds (queued for 6 seconds)
Status Name Job ID Coverage
  Check
passed check #30193

00:00:15

 
  Build
passed build_long: [baseline iso] #30196
fast-single-thread

00:17:35

passed build_long: [baseline netboot] #30197
fast-single-thread

00:15:53

passed build_long: [releng iso] #30198
fast-single-thread

00:32:15

passed build_long: [releng netboot] #30199
fast-single-thread

00:29:54

passed build_short: [baseline bootstrap] #30194

00:13:19

passed build_short: [releng bootstrap] #30195

00:13:02