I can not edit data in firebase

Hi everyone,
I made an aplication where I save some information on firebase. I can add user on firebase without any error. But I have some errors when I try to edit data on Firebase.
Here my aplication.

No problem when adding.

import { Component } from '@angular/core';
import { NavController, NavParams, ActionSheetController } from 'ionic-angular';
import { AngularFireDatabase } from 'angularfire2/database';
import { EdicionPage } from '../edicion/edicion';

@Component({
  selector: 'page-login',
  templateUrl: 'login.html',
})
export class LoginPage {
  arrData = [];
  $key?:string;
  myInputName: string;
  myInputNumber: number;
  usuarios:any = [];
  llave = [];
  union:any = {
    id:"",
    nombre:"",
    edad: ""

  };

  constructor(public navCtrl: NavController, 
  				public navParams: NavParams,
  				private afDB: AngularFireDatabase,
          private action: ActionSheetController) {
 
    this.afDB.list("myUsers").valueChanges().subscribe(_data =>{
      this.arrData = _data;
      console.log(this.arrData);
  });
    this.afDB.list("myUsers").snapshotChanges().subscribe(_data =>{
      this.llave = _data;
      console.log(this.llave);
   });
   
  }
  btnAddClicked(usuarios){

    console.log(usuarios);
    this.afDB.list("myUsers").push(/*this.usuarios*/
      {myInputName: this.usuarios.myInputName,
       myInputNumber: this.usuarios.myInputNumber
      });
    this.usuarios.myInputName ="";
    this.usuarios.myInputNumber="";
  }


btnAction(i){
 console.log(i);
  this.action.create({
    title:`${this.arrData[i].myInputName}`,
    buttons: [
    {text: "Editar",
    handler: ()=>{

      console.log(this.arrData[i].myInputName);
       this.navCtrl.push(EdicionPage, {i:this.llave[i]});
 
    }
  },
    {text: "Borrar",
    role: "destructive",
    handler: ()=>{
      this.afDB.list("myUsers").remove(this.llave[i].key);
       console.log(this.llave[i].key);
   
    }

my problem is edding. Here my code:
(diferent ways to edit data)

import { Component } from '@angular/core';
import { NavController, NavParams } from 'ionic-angular';
import { AngularFireDatabase } from 'angularfire2/database';
import { LoginPage } from '../login/login';

@Component({
  selector: 'page-edicion',
  templateUrl: 'edicion.html',
})
export class EdicionPage {
item;
arrData = [];
aEditar: any =[];
myInputName:string;
myInputNumber:string;

usuarios:any = [];
  llave = [];

  constructor(public navCtrl: NavController, 
  			  public navParams: NavParams,
  			  private afDB: AngularFireDatabase) {/*
    this.aEditar = afDB.list("myUsers");

    this.aEditar.id = this.navParams.get('key')
    this.aEditar.myInputName = this.navParams.get('myInputName')
    this.aEditar.myInputNumber = this.navParams.get('myInputNumber')

*/
    
  	this.item = navParams.data.i;
  	console.log(this.item);
    this.afDB.list("myUsers").valueChanges().subscribe(_data =>{
        this.arrData = _data;

    this.aEditar=(this.arrData[this.item]);
    console.log(this.aEditar);
   });
    this.afDB.list("myUsers").snapshotChanges().subscribe(_data =>{
      this.llave = _data;
      console.log(this.llave);
  

    });

  }

	btnEditClicked(aEditar){/*
    this.afDB.list("myUsers").update(this.aEditar.id, {
       myInputName = this.aEditar.myInputName,
       myInputNumber = this.aEditar.Number 
    })*/
      
   //this.afDB.list("myUsers").update(aEditar.key, aEditar);
	//this.afDB.database.ref("myUsers/"+aEditar.llave).set(this.aEditar);

	console.log(this.llave);
	this.navCtrl.push(LoginPage);
	}
  ionViewDidLoad() {
    console.log('ionViewDidLoad EdicionPage');
  }

}

edit html

<ion-content padding>

  <ion-item>
    <ion-label floating>Nombre</ion-label>
      <ion-input [(ngModel)]="aEditar.myInputName" type="text" value="{{aEditar.myInputName}}"> </ion-input>
  </ion-item>

  <ion-item>
    <ion-label floating>Number</ion-label>
      <ion-input type="number" [(ngModel)]="aEditar.myInputNumber" value="{{aEditar.myInputNumber}}"></ion-input>
  </ion-item>
  
  <button ion-button block outline item-end icon-start (click)="btnEditClicked(aEditar)" ><ion-icon name="cloud-upload"></ion-icon>Añadir a Firebase</button>

</ion-content>