The stealth telecommunications team arrived in Misurata after a stomach-churning 30-hour fishing boat ride from Malta.
Amid rocket fire and despite power cuts, they worked 12 hours a day alongside local engineers, setting up satellite dishes and other equipment. As a result, residents whose mobile phone networks were disabled by Colonel Muammar Qaddafi's forces may soon be able to call their neighbours.
Ousama Abushagur, a 31-year-old Libyan-American telecoms executive living in Abu Dhabi, and his global network of donors, vendors and engineers pulled off the same feat three months ago in Benghazi. Phone lines in the de facto rebel capital in eastern Libya also had been cut.
In June, the team brought their rogue network to Misurata, Libya's third-largest city. For months, the city had suffered some of the worst fighting since Col Qaddafi and rebel forces began battling in February.
The local workers are now running tests and verifying the identities of tens of thousands of SIM card holders in the rebel-held city before turning on the network.
Two engineers came to Dubai this month for training on how to maintain the network.
"Everybody is just trying to help the country, whatever it is," from cleaning streets to baking bread, said Mohanned Saad, 28, one of the trainees. "We found we could contribute our expertise. People still have the spirit from the first days of wanting to get rid of Qaddafi. They want him out even more now."
Much of that determination was forged in the hardship of living under siege, said Hossain Eljamal, 29, who also came to Dubai for training. When residents first rallied against Qaddafi in February, and soldiers fired at them, larger crowds gathered the next day, he said.
Later that month, Col Qaddafi's forces broke into Misurata, and residents fled to stay with relatives and friends outside the city centre. Twenty-five people, ranging from ages 1 to 78, crammed into Mr Eljamal's five-bedroom family home. They went for more than a week without power, he said. To buy bread, they queued for hours. Young men skipped meals.
Mr Eljamal's two brothers volunteered with ad hoc committees to distribute aid and medicine.
He helped with the "information committee", collecting photos from the fighting and sending them to international media outlets via satellite.
At the same time, though, he had trouble reaching even his sister's family just 15km away, he said. For a month, they had no contact.
By early June, with Col Qaddafi's forces pushed out but still firing rockets into Misurata, Mr Eljamal and others returned to the city. They formed committees to restore utilities. One team fixed the electricity. Another set up a system of walkie-talkies. A third re-established the landline network.
Mr Eljamal and Mr Saad's team - the mobile unit - began repairing base stations around town. Mr Abushagur and his team of experts arrived on a fishing boat on June 10.
They brought several million dirhams worth of satellite dishes, batteries and a "rapid-deployment network kit" - core telecoms equipment the size of a briefcase - intended for use in a crisis. Setbacks included the discovery that they had forgotten some equipment, which took a week to arrive.
Once the network was ready, they met resistance from the people they were trying to help. Some local leaders feared Col Qaddafi spies would tap the network. Eleven people were assigned to check the identities of every individual - two from each family - to whom SIM cards were being allotted. The engineers declined to say how long that would take.
After that process is complete, Misurata residents will be able to call internationally on their mobile phones. But telecom providers worldwide will have to link their systems with the new one from Misurata so that outsiders can call in, said Christophe Justens, a vice president of the firm that will invite providers to establish the links.
The company so far has linked Misurata landlines with networks in the UAE, Qatar, Egypt and Tunisia. For now, the engineers working on the mobile system rely on landlines, costly satellite phones and limited-range walkie-talkies, which can make it hard to find each other.
"Sometimes you'll lose a whole day trying to chase a guy," Mr Abushagur said.