Just got off the horn with Everlink support. Sorry it took so long
ops: They said they haven't had any reports of voice quality issues with 1055. The person I spoke to said that he was using the 1055 image on his phone with no trouble. His advice was to hard reset and see what happens. If it doesn't improve after the reset and you believe that the GSM software was corrupted by the 1055 image, fill out an RMA on the everlink.com website.
Also, there is a 1058 image in the wild, but it isn't official yet. I check the ftp site every couple of days, so I'll post as soon as something hits.