Nucleo F401 only works right after flashing, not after power cycle

[espruino-discuss3]

Posted at 2016-04-17 by DrAzzy

Using official F401 bin.

All I get after flashing is "Connected" and a single >.

I remember the issue with drag and drop, so I've tried both drag and drop and ST-Link flashing, no joy either way. Anyone know what's wrong?

The ones from my nightly builds seem to work...

[espruino-discuss3]

Posted at 2016-04-17 by @gfwilliams

Did you update the firmware on the Nucleo itself? ST decided to add extra checks to their bootloader which makes it refuse to upload perfectly working code.

I was hoping they'd revert them, but presumably they haven't.

Bug here: espruino/Espruino#742

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Posted at 2016-04-17 by DrAzzy

Hm, in fact, that doesn't seem to explain things. After I flash, it does actually work, until I power cycle it, at which point it stops working again. Mysterious. I continue to investigate.

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Posted at 2016-04-18 by DrAzzy

Log from incident, this was the first time I was able to connect and get more than just the > after flashing several times, and trying to connect without powercycling:

Connected
>I�lInvalid saved code in flash!
>
=undefined
>  //Oh hey, it's not non-responsive. Better reset() and save()!
=undefined
>reset()
=undefined
 _____                 _
|   __|___ ___ ___ _ _|_|___ ___
|   __|_ -| . |  _| | | |   | . |
|_____|___|  _|_| |___|_|_|_|___|
          |_| http://espruino.com
 1v85.75 Copyright 2016 G.Williams
Espruino is Open Source. Our work is supported
only by sales of official boards and donations:
http://espruino.com/Donate
>save()
=undefined
Erasing Flash...
Writing.....
Compressed 86016 bytes to 2657
Checking...
Done!
>
=undefined
>  //great, I'll disconnect, unplug+replug it, and reconnect.... 
Disconnected
Connected
> //and now this is all I see, typing has no effect. 
Disconnected
Connected
>

Any ideas?

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Posted at 2016-04-18 by tve

Erase all flash and start over...

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Posted at 2016-04-18 by DrAzzy

No change. Erased using ST-Link, flashed again using ST-Link (which as I understand should write it correctly? I thought that was the conclusion above?)

Same behavior on official and my nucleo nightly.

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Posted at 2016-04-18 by @gfwilliams

Not sure what to suggest - so it's also broken on the 1v85 release?

What happens if you hit reset? On the nucleos a reset won't cause USB to be disconnected, so you'll see anything that gets written, even if it is only a few characters.

... and it's not just that you set baud rate to 115200 for ESP8266 and didn't change it back?

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Posted at 2016-04-19 by DrAzzy

I'll check reset.

Baud rate is unchanged - and as shown in the log, it worked briefly, and then went back to not working. I don't think i've ever changed the baud rate that the IDE uses - I always hopped on hterm to set the wifi stuff, and then just connected over telnet.

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Posted at 2016-04-19 by @gfwilliams

Does the onboard LED flash just after reset? That should show that Espruino finished initialising the hardware.