setup 1:set the revison to 0
step 2: install ios with low revision
preparations complete,press A to start setp1...
installing ticket...
setting the revsion to 0...
error:es-addtitlefinish returned -1017
error:could not set the revision to 0
downgrade failed
press any button to exit...
请问这个问题怎么处理?前面步骤都完了就是选ios36,按1,选downgrade ios15,一路点A时出现的