If you bet on a BlackBerry stabilisation, congrats. After reporting a solid second quarter on Friday, BlackBerry shares have rallied 75 per cent since December. If you did not make that bet, too bad. Now you have to bet on BlackBerry’s growth – after figuring out just what business the company is in.

With a cash flow deficit of just $36m and a loss of 2 cents in the second quarter, chief executive John Chen’s promises of break-even cash flow by year’s end, and profitability by 2016, seem plausible.

Even with BlackBerry shares rallying 7 per cent on Friday, the worry is revenue, which was a disappointing $916m. The respectable cash flow and earnings figures have come from cleaning up the business – that is, slashing 40 per cent of its workforce.