Read this article and answer this question Geographic knowledge of the Canary islands coalesced with these expeditions.  La Gomera and El Hierro are depicted in the 1367 portolan of the brothers Domenico and Francesco Pizzigano.   The Catalan Atlas of 1375  shows the Canaries almost completely and accurately mapped . The eleven islands are named in the Catalan Atlas  as Graciosa ,laregranza , rocho , Insula de lanzaroto maloxelo , insula de li vegi marin , forteventura , Insula de Canaria , Insula del infernio , insula de gomera , insula de lo fero .  The name 'tenerefiz' is first given alongside 'Infierno' in the 1385 Libro del Conoscimiento. During the 1370s, when Portugal and Castile were engaged in dynastic wars following the assassination of Peter I of Castile, Portuguese and Castilian privateers were dispatched against each other, several of which made detours to the Canary islands for shelter or slave-raiding jaunts.  Ignoring the 1344 bull, Ferdinand I of Portugal granted  the islands of Lanzarote and La Gomera to the adventurer 'Lançarote  da Franquia' .  This Lanzarote made an attempt to seize the islands and is reported to have engaged in fighting with "Guanches and Castilians" there. There are several other expeditions, since determined to be apocryphal.  Among those deemed purely legendary are:
What was the last of the Canary Islands to be listed as of 1385?
tenerefiz