Future debug board and deprecating write-only

[Andy Green]

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Hi folks -

I awoke today putting two and two together about how I think we should
deal with NOR, brickage and the debug board in future.

Taking GTA02 as an example, what I would have proposed if I realized
this earlier would have been to throw out the NOR flash completely.  Now
the people that like the NOR flash defend it as the ultimate safety
against brickage, however that is not true.  JTAG is the genuine
ultimate safety against brickage already.

A better solution would have been to throw out the NOR and place an
internal USB micro B socket on the PCB (not reachable while in the case)
where the debug connector is now, and with the dual FTDI as found on the
debug board.  In short we place a "debug board" on every main board in
the region that has the debug connector right now.

It seems from discussing this with Werner in .tw that much of the
current debug board is waste, for example the whole USB hub, the two USB
A connectors and probably a bunch of other stuff.  If we just placed:

 - the FTDI chip
 - micro USB conn
 - 6MHz xtal
 - EEPROM
 - 74*125 dual buffer

on the main board, *every* phone would have a "debug board" built in and
can be debricked, and the cost is likely about the same as the NOR flash
it replaced for better functionality (and the removal of the need for a
debug board as a product).  There appears to be space enough considering
the NOR disappears.

Then the complaint would be that the host-side tools are very poor...
well crikey the amount of time we spent dealing with NOR U-Boot we could
have fixed that for a much wider and longer-lasting benefit.

Getting rid of the "debug board" as an item and integrating it into the
main board is also a good way in terms of making every phone more
hackable directly.

- -Andy
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