Japanese electronics giant Sony served up a rare piece of good news this week, posting a quarterly profit for the first time in three years and signaled better times ahead by hiking its full-year forecast.
Thursday's announcement may have cheered markets - Sony shares rose as much as 4 percent in Friday's Tokyo session - but industry watchers remain unconvinced about its profit turnaround.
Sony made a net profit of 3.5 billion yen ($35 million) in the April-to-June quarter, compared to a 2.46 billion yen loss in the year ago period. The firm attributed the gains to a weaker yen, which has declined around 15 percent against the dollar this year, and a rise in smartphone sales at home.
(Read more: Sony forecasts profit to hold steady this year after return to black)
But the maker of PlayStation consoles and Bravia TVs acknowledged the harsh market conditions for consumer electronics, cutting full-year sales targets for products from PCs to televisions to video cameras, and left its full-year profit forecasts unchanged even as it lifted its revenue forecast more than 5 percent.
Paul-Jon McNealy, CEO and founder of Digital World Research, said Sony's profit is a "one-off" and masks the tech giant's fundamental flaw, which is that its vast electronics business remains weak.
(Read more: Change at Sony: Start of third leg of Abenomics?)
"The problem is it's a one-off uplift. This was the best quarter in three years for all Japanese consumer companies, not just Sony, and it was hugely driven by the yen," said McNealy.