The printer’s manuscript clearly reads Comron both times in Ether 14:28. The 1830 compositor, however, set the name as Comnor, which has been retained throughout the textual history.
We have already noted that in both manuscripts Oliver Cowdery frequently wrote his n’s as r ’s and vice versa (see, for instance, the discussion under Mosiah 2:15–16). Thus it is possible that the name here in Ether 14:28 could have theoretically been one of four possibilities: Comron, Comnor, Comnon, and Comror. There is only one instance where Oliver mixed up mr and mn, namely, in the fifth occurrence of the name Zerahemnah in the original manuscript (in Alma 43:53). There he initially spelled the name as Zerahemrah, but then he immediately overwrote the r with an n (see line 15 on page 311ªof 𝓞). For all other (extant) occurrences of Zerahemnah, in both manuscripts, this name was correctly spelled the first time. Thus there is not much evidence that the spelling Comron in the printer’s manuscript could be an error for Comnon, Comror, or Comnor.
Comparing the spellings Comron and Comnor with other Nephite names and words in the Book of Mormon, we find examples ending in either -ron or -nor; in the following list, the names and words that have an internal mr or mn sequence are set in bold:
Thus there are three examples of -mnor and one of -mron. There is also one name ending in -mnon, namely, Shemnon, but none ending in -mror. Moreover, none of these examples show any textual variation with respect to the n and the r. All of this argues here in Ether 14:28 that the earlier Comron is definitely possible (it matches Emron) and should therefore be adopted in the critical text.
Summary: In accord with the reading in the printer’s manuscript, restore the spelling Comron for the name of the hill in Ether 14:28.