Firmware Over-the-Air (FOTA)

Looked at your .js code... wondered why you use WREN for just reading the busy flag...

AT25.prototype.isBusy= function() {
	if (add===undefined) {
		add=this.ca;
	}
	var t=new Uint8Array([0]);
    this.spi.send(6,this.cspin); //WREN
//  this.spi.send(6,this.cspin); //WREN
	var i=0;
	t[i++]=0x05;
  var ov=new Uint8Array([255]);
  do
  {  
     
     ov[0]=this.spi.send(t,this.cspin); 
  }while((ov[0] & 0x01) == 0x01);
    print("\r\n ov is :" +ov[0]);
	
};

I could imagine that this could mess up the whole thing... I would just go for this simple approach:

// returns true if busy
AT25.prototype.isBusy= function() {
  return ((this.spi.send([0x05],this.cspin)[0] & 0x01) === 0x01);
}

You can then use this method in the read, write, erase, etc. at the begin like this:

...
while (this.isBuys()) { "";  }
...

Invoke .isBusy() Is no big deal, because you want to - and have to - waste time anyway...

If you do not like the extra invocation, you could just imbed the code in the while condition:

...
while ((this.spi.send([0x05],this.cspin)[0] & 0x01) === 0x01) { ""; }
...

@Gordon, is the below code about the same as the above - assuming both work?

...
while ((this.spi.send(5,this.cspin)[0] & 1) === 1) { ""; }
...

And if both work, which one would you prefer?

I'm asking, because of the conversion of literal ints to uInt8?