The Quansheng’s UV-K5 radio can be modded with the click of a mouse. IEEE Spectrum looks at the handheld:

The UV-K5, released last year, might be the most hackable handheld ever, with a small army of dedicated hams adding a raft of software-based improvements and new features. I had to have one, and $30 later, I did.

Like Baofeng’s 5R, Quansheng’s K5 as a radio transceiver is fine. (I’m using K5 here to refer to both the original K5 and the new K5(8) model.) The key technical distinction between the 5R and K5 is a seemingly minor design choice. With Baofeng’s 5R, the firmware resides in read-only memory. But Quansheng stores the K5’s firmware in flash memory and made it possible to rewrite that memory with the same USB programming cable used to assign frequencies to preset channels.

The prospect of an updatable radio dangled an irresistible temptation for folks to start reverse engineering the firmware and hardware so they could try writing their own code. Modifications to date have generally taken the form of patches to the official firmware, rather than wholesale rewrites. With the official firmware taking up most of the radio’s 64 kilobytes of flash memory, such mods have to fit into less than 3 KB.

Read more in IEEE Spectrum here.