“Healthy demand” for the iconic Apple iPhone has helped Japan’s 3rd largest carrier in terms of subscribers to swing to a fiscal Q4 net profit claimed Softbank on Tuesday reports an article over on the WSJ.

However, Softbank also remarked that the costs of tidying up remnants of their “old school 2G operation” weighed on their bottom line. In the January to March quarter, Softbank showed an Y1.85 billion net profit along with an operating profit of Y99.55 billion.

The large gap between operating and net profit is attributed to a “special loss” related to their move away from their extinct 2G mobile service.

The reported Y1.85 billion Q4 net profit is a reversal of the previous year’s posted net loss of Y15.01 billion mainly due to expenses related to the redemption of bonds which were inherited during Softbank’s acquisition of Vodafone’s Japanese operations.

During a press conference the president of Softbank, Masayoshi Son acknowledges the “crucial roll” the Apple iPhone will take in Softbank’s expansion by saying, “The iPhone is central to our strategy to lead the mobile Internet scene.”