"We are not giving up on the iPhone's potential for evidence until all viable efforts have been exhausted,' Pamela Cohen tells PEOPLE
Credit: Courtesy Coast Guard(2)

It’s another heartbreak in a search for answers for the families of two Florida teens missing at sea since July.

In a Tuesday night conference call, a team leader at Cupertino, California-based Apple, Inc. informed attorneys for the families of Austin Stephanos and Perry Cohen that they were unable to restore Austin’s recently recovered iPhone 6 to working order.

The phone and other personal effects were found in a latched compartment of the 19-foot Seacraft boat that the boys, longtime friends who boated and fished together often, took off in from Jupiter Point on July 24. Crewmembers of a Norwegian freighter recovered the capsized boat about 100 miles off the Bermuda coast in March.

“Although they were unable to restore the phone to a functional state, I want to thank Apple, Inc. for their hard work and generous assistance,” Austin’s father, Blu Stephanos, posted on a Facebook page for the AustinBlu Foundation on Wednesday. “I see no reason to doubt that every possible means was employed to get Austin’s phone working again. It’s our understanding that Apple had a team assigned to the iPhone around the clock, and for that we are truly grateful.”

Pamela Cohen, Perry’s mother, told PEOPLE Wednesday, “We learned yesterday that Apple went as far as they could to try to get Austin’s iPhone working, which, as Apple advised, was the first step in the process of retrieving information that might help us understand what happened to the boys.

“For the generous efforts by Apple’s engineers, who we understand worked tirelessly to try to help us, we are so very grateful.”

But the effort to retrieve data from the phone may be far from over. Components of the phone, which the Apple team disassembled in order to run the diagnostics, clean and restore components and perform a chemical workup, soon may undergo a second analysis, pending an agreement between the two families.

“According to Apple, there are other experts in the field who may be able to pick up where Apple left off, to continue the work,” Cohen said. “Apple has offered to securely hand the iPhone off to an expert in this technology if the families can agree on such an expert. We look forward to working cooperatively with Austin’s family toward this transition.”

Still, data retrieval remains doubtful, said Michael Pike, attorney for the Stephanos family, noting that the phone ran on Apple’s IOS 8.4 operating system.

“IOS 8.4 has not been, for lack of a better word, cracked by any forensic expert or Apple. It is a very strong operating system and if the phone is password-protected, like this one was, even if you get it powered on, Apple does not have a way currently to bypass the password,” Pike told PEOPLE. “We are certainly thinking about other options, but we do not have great hope as to whether or not another company can power on this phone or extract information from it. We may very well entertain other options, but the reality of it is that it will likely be unsuccessful.”

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After its recovery, the phone had been airmailed to the Florida Fish and Wildlife Conservation Commission, the lead agency in the case. Because the case is not currently considered a criminal one, the agency returned the phone to Stephanos in late April without performing a forensic analysis. That move prompted Perry’s mother, Pamela Cohen, to file a lawsuit, asking that the phone be returned to law enforcement until it could be examined. Any data retrieved could offer clues to just what happened to the boys the day they vanished.

In an April 29 hearing, Palm Beach County Judge Gregory Keyser ordered the phone sent via FedEx to Apple with both families granted access to tracking information and a report detailing the results of the manufacturer’s analysis to be filed with the court.

Despite the challenges involved, Cohen remains hopeful that continued efforts to retrieve data from the phone and to forensically analyze the boat, expected to arrive in Port Everglades next week, may yet yield answers.

“As I’ve said before, I owe it to Perry to exhaust every possible avenue in pursuit of finding out what happened to him,” she told PEOPLE. “We are not giving up on the iPhone’s potential for evidence until all viable efforts have been exhausted.”

Stephanos said, “Needless to say, we were disappointed, having hoped to get some information or maybe just some final memories from Austin’s phone. “But the fact that it can no longer function as a phone doesn’t diminish its value as a cherished memory of my beloved son. It’s a small piece of him; something he used to call me at night when he needed to talk to someone, something he put his stickers on and carried with him every day. As any parent would understand, to me, it’s not a broken phone, but a memory of my son that I will hold close to my heart and treasure for the rest of my life.”