That is the first time I have seen the verb unbrick.
I thought it might come from the root "to brick" illustrated by the following anecdote:
An American needed to move supplies across the desert by camel. Experts told him that the journey would require 8 days with no available water on the route, and was impossible since camels can only go without water for 7 days. But the camel drivers at a local bar all agreed that the journey was routinely done, and that they had never lost a camel or a cargo.
The American loaded his camels and confidently set forth. For 7 days everything was going fine, but on the morning of the 8th day, one by one, his camels keeled over and died. Sitting on the desert sand with the stench of dead camels surrounding him, he was astonished to see a local camel driver coming over the dunes.
"How is it that your camels are still alive," he asked, "when all my camels died by this time?"
"Well," said the driver, "did you brick your camels?"
"What do you mean, brick my camels?," said the American.
"Well everyone knows that camels must be bricked to make this journey. When you start the journey you must lead the camel to the watering trough. He will normally drink enough water to last for 7 days. As you sense that he has almost finished drinking, you must approach the camel from behind holding a brick in each hand. At the last moment you slam the bricks together on his testicles. The sudden gasp he takes will cause him to suck up an extra day worth of water, and you can extend your journey by a day."
"My god," cried the American. "doesn't that hurt?"
"Of course not," said the camel driver, "Well only if you get your thumbs between the bricks."