1) An aphetic spelling of ‘amend’, with meanings such as recompense, improve, make amends for, set to rights.
1536 to Sir John Watson xijd and what as my wife wyll mend hym with all, Burton
1541 to John my sone my best fool. To Richarde my sone my secunde foyll and to Robert my sone the thirde fool and his moither to mende him because his foil is warste, Monk Fryston
1556 bated his horse upon the brode balke whilste he mendid his wooll packes, Welburn
1558 I wyll that the pore folks of the churche rawe be mended with bygge ... that Jenet Atkynson be mendyd with some of my clothes, Sedbergh.
2) To make the fire up, adding fuel and controlling the draught.