Clear a MDBT42Q module from all code?

[espruino-discuss]

Posted at 2020-09-09 by JohanWinas

So, after a lot of debugging I have now realised how the "Flash (always)" works and what a "reset()" actually means. It's not a reset or reboot, it's a system clear. And my broken code is now written with "Flash (always)" so my two dev modules are now bricked.

So how do I get them back? A DFU update does nothing.
Is there any other way to program the module and clear the flash???

[espruino-discuss]

Posted at 2020-09-09 by @fanoush

How 'bricked' they are? you cannot access Espruino console over serial or bluetooth - wherever the active console is? You cannot press ctrl+c on the console (left side in web ide or over serial teminal) to get debug prompt debug>? see https://www.espruino.com/Debugger

If you can break into debugger after startup to see the debug> prompt then your running code is stopped and you could hopefully run print require("Storage").eraseAll() from debugger to clear the storage.

With serial console it may be easier - reset or poweron the module with serial already open and immediately try ctr+c

[espruino-discuss]

Posted at 2020-09-09 by @MaBecker

If you have a MDBT42Q Breakout

• remove power
• press button
• power up
• release button when red led is switched off

this procedure will startup the firmware without loading your code and give you the possibility to connect and remove the code.

[espruino-discuss]

Posted at 2020-09-09 by @fanoush

Oh, maybe that will work too when there is original espruino bootloader which clears it before jumping into Espruino?

Otherwise when BTN1 is held at startup time the code is skipped except the code marked as "flash always", that one still runs even with button held. This was confimed by some unlucky guys and is also described here https://www.espruino.com/Saving - Boot Process - holding button is exactly like running reset() (sets hasBeenReset ) so .bootrst still runs.

[espruino-discuss]

Posted at 2020-09-09 by JohanWinas

First of it turns out the webIDE had gotten it self in some state, closing the browser and opening it again allowed me to connect and get a prompt, at least long enough to run reset() to clear out the bad code.
So at least one of the modules are now running again, will check on the other one later.

I have now installed the chrome app, and that seam to be more stable and works better.

[espruino-discuss]

Posted at 2020-09-09 by @fanoush

so you can run require("Storage").eraseAll() that will clear everything - the .bootrst one and also one possibly created by running save()

[espruino-discuss]

Posted at 2020-09-09 by JohanWinas

Tried it, this is the output..

>require("Storage").eraseAll()
=undefined
Uncaught SyntaxError: Got [ERASED] expected EOF
 at line 1 col 1
[ERASED]...
       ^
in function called from system
Uncaught SyntaxError: Got [ERASED] expected EOF
 at line 1 col 1
[ERASED]...
       ^
in function called from system
Uncaught SyntaxError: Got [ERASED] expected EOF
 at line 1 col 1
[ERASED]...
       ^

---

And it goes on and on like that.

[espruino-discuss]

Posted at 2020-09-09 by @fanoush

well yes, so just reboot/powercycle it, if you had code running from flash this was all erased at the point of calling eraseAll so code inside setWatch, setInterval is suddenly hitting empty flash where it expected javascript program to be

[espruino-discuss]

Posted at 2020-09-09 by @MaBecker

what is the result of

require("Storage").list()

[espruino-discuss]

Posted at 2020-09-09 by @MaBecker

here is the information about startpoint and size of the save code

https://github.com/espruino/Espruino/blob/eca6aae8104ddaca66dfe317d3b76243962f4332/boards/MDBT42Q.py#L66

maybe you can use the flash lib to clear the pages

http://www.espruino.com/Reference#Flash

[espruino-discuss]

Posted at 2020-09-09 by @fanoush

you shouldn't need to, that's what Storage.eraseAll does

[gfwilliams]

Posted at 2020-09-14 by @gfwilliams

As @fanoush says, require("Storage").eraseAll() will get rid of everything - but if you had stuff in RAM then that will still run, and if it references stuff that was in flash you'll get the Got [ERASED] expected EOF error - a simple reboot will fix it permanently.

The easiest fix for that is actually just to do this to clear the device:

require("Storage").eraseAll();reset()