diff --git a/firmware/FIRMWARE.ZX1 b/firmware/FIRMWARE.ZX1
index 64138ca..19bbfc0 100644
Binary files a/firmware/FIRMWARE.ZX1 and b/firmware/FIRMWARE.ZX1 differ
diff --git a/firmware/firmware.asm b/firmware/firmware.asm
index fe9da17..46e3569 100644
--- a/firmware/firmware.asm
+++ b/firmware/firmware.asm
@@ -249,8 +249,8 @@ start   ld      bc, chrend-sdtab
         rrca
         ld      a, h
         adc     a, a
-        or      $c0
-        ld      (scnbak), a       ; lo pongo a 28Mhz
+        or      $80
+        ld      (scnbak), a       ; lo pongo a 14Mhz
         out     (c), a
         ld      de, fincad-1    ; descomprimo cadenas
         ld      hl, sdtab-1
diff --git a/firmware/strings.asm b/firmware/strings.asm
index ead721b..ff42e53 100644
--- a/firmware/strings.asm
+++ b/firmware/strings.asm
@@ -1,6 +1,6 @@
 cad0    defb    'Core:             ',0
 cad1    defm    'http://zxuno.speccy.org', 0
-        defm    'ZX-Uno BIOS v0.62', 0
+        defm    'ZX-Uno BIOS v0.63', 0
         defm    'Copyleft ', 127, ' 2017 ZX-Uno Team', 0
         defm    'Processor: Z80 3.5MHz', 0
         defm    'Memory:    512K Ok', 0
@@ -35,7 +35,7 @@ cad8    defm    $10, '                         ', $10, '              ', $10, 0
 cad9    defb    $14, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11
         defb    $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $18, $11
         defb    $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $15, 0
-        defb    '   BIOS v0.62    ', $7f, '2017 ZX-Uno Team', 0
+        defb    '   BIOS v0.63    ', $7f, '2017 ZX-Uno Team', 0
 cad10   defb    'Hardware tests', 0
         defb    $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11, $11
         defb    $11, $11, $11, $11, 0