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Old 05-01-2016, 05:37 PM   #26
geekmaster
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Posts: 6,433
Karma: 10773670
Join Date: Nov 2011
Location: Multiverse 6627A
Device: K1 to PW3
Quote:
Originally Posted by dram View Post
How then it could work before executing 'eraseall'? That was biggest confusion about my converter. It was working without any problem, so I didn't think that it might be the reason.
With a good ground in the kindle (not on the TTL serial connector), I found that TTL worked okay in ONE DIRECTION, but not the other. It could be that your TxD and RxD LEDs are buffered, rather than being directly driven by the kindle TxD line. Or perhaps your LEDs are using a higher value of resistor than mine did. Consider yourself lucky if it "just worked", when the linked info showed it as a 3.3v (minimum) adapter.

On a K5 (Touch) or earlier, erasing your entire flash would be relatively trivial to fix, because you press a "magic key" during hard reset to enter USB downloader mode. Though the PW uses the same processor (i.MX508) as the K5, it has no keys (and therefore no "magic key").

However, the "magic key" is likely wired to one of the inputs on the SoC that determine boot mode, and finding that pin on the PW SoC (especially somewhere on the PCB that you can connect to) may allow you to enable USB downloader mode even on a PW (or later). AFAIK nobody has done this yet, but it may be possible.

Meanwhile, erasing all your flash on a newer kindle is like playing Russian Roulette with all chambers loaded.

Last edited by geekmaster; 05-01-2016 at 05:41 PM.
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