NEW YORK — Bank of America’s home page and online banking service appeared to be back to normal late Wednesday. But the bank still declined to explain why customers had problems accessing their accounts for six days. A spokeswoman for the company, Tara Burke, also would not confirm whether the issues had been fully resolved or whether any customers were still experiencing slowness. She said only that online banking was now available. That was in contrast to the bank’s multiple statements since Friday that the site was fully restored, only to have problems resurface. Burke had ruled out hacking as a potential cause early on and said customers’ personal and financial information wasn’t compromised. But she said the company doesn’t disclose the “root causes” for site problems. Bank of America Corp., based in Charlotte, North Carolina, is the largest U.S. bank by deposits and has 29 million online customers.