Andy Green wrote: > *every* phone would have a "debug board" built in
Aaah, good ideas never die :-) I actually suggested moving the debug board inside the Neo a long time ago. The reasons why it was shut down were the size of the FTDI chip, the cost of it, and size+cost+issues of the USB hub, with issues being that the USB power budget wouldn't be shared in the normal way. The idea of putting a second USB connector didn't occur to me back then. I like the simplicity of that. It would indeed eliminate the need for the hub chip and simplify the power budget. You'd then need two upstream ports, but even if you only have one upstream port, you could just use a small unpowered hub. A solution involving FTDI+USB connector+glue logic will take a lot more PCB space than just the NOR. Also, the NOR isn't necessarily optimal in the sense that, had our NAND better built-in protection features (like most new NAND chips do), we wouldn't have needed an extra chip just for that. So I wouldn't expect us to need a separate memory chip just for recovery in the future. Instead, the first sector of the memory chip (maybe in and MCP), be it NOR or NAND, would just contain a bit of code that locks down the pages needed for recovery and then proceeds with normal execution. Unlike our "old-style" NAND, more modern chips, ironically including our NOR, have the option of write-protecting a page such that it can't be unprotected by anything but a reset. We didn't use that feature in our NOR on the grounds of it being simpler and safer to just do everything in hardware, but perhaps that simplicity was a bit overestimated. A software-based protection scheme would also allow us more flexibility in how we select the boot mode and how we disable the write protection. E.g., instead of requiring a "hardware key", one could just disable write protection by, say, holding down AUX and tapping S-O-S in morse on the touch screen. So even if we can't have the integrated debug board in future products, we should be able to have a considerably less cumbersome recovery option than in GTA02. If we can pull off the integrated debug board, that would be great, of course. Getting rid of the fumbly FPC would be a win already. - Werner
