By "radio OS" I assume you mean the baseband controller firmware?
It would be nice if it was open source, but it's a bit more understandable than the Intel ME. The baseband firmware often has regulatory requirements the rest of the phones doesn't have. It comes from a different vendor, and is compartmentalized. I too would like it to be open source, but it seems like a different situation.
I'll grant there's an argument for requiring signed code for GSM-capable hardware on consumer devices; we don't want people accidentally turning their device into a jammer.
But:
1. closed-source driver code always has security holes. Having insecure devices is as bad for public policy as jamming.
2. if I really want to jam cell signals I can take the door off my microwave. (kids listening at home -- don't do this). Anyone who's ever flashed an android device will agree that it's easier to hotwire the microwave than build bootable code for the handset.
3. the radio controller runs a sophisticated RTOS that (I assume) can read the phone's RAM and execute wacky RPC. And most cellular networks have experimented in the past with some form of rootkit or spyware. Dear Verizon: I paid for the device. Let me own it.
One answer that compromises between consumer needs & FCC needs is to say signed code has to be open source and verified-build.
I'm guessing there's a lock-in argument for the radio chipset creator. Being the only vendor of software for your hardware means vertical integration, i.e. there are fewer companies expert in any part of your stack.
The regulatory requirements are bullshit. I can build out of spec transmitters in my garage. If I use one, I get in trouble with the FCC.
The requirements as they stand are nothing more than an excuse for shitty networks to spend less on reliability and security while providing a convenient backdoor for state-level actors.
How difficult do you think it is to build jamming equipment? If you are technical enough to install new firmware, you can follow directions to block cell phone calls in your immediate vicinity. It just takes a Google search and a soldering iron.
Yes, but sometimes regulators mandate that firmware can't be changed by the user for example. So, while perhaps not better, I can see that it's a different situation that the Intel ME.
It would be nice if it was open source, but it's a bit more understandable than the Intel ME. The baseband firmware often has regulatory requirements the rest of the phones doesn't have. It comes from a different vendor, and is compartmentalized. I too would like it to be open source, but it seems like a different situation.