diff --git a/src/rp2040/hardware_regs/include/hardware/regs/pio.h b/src/rp2040/hardware_regs/include/hardware/regs/pio.h
index 8b4829f..b231882 100644
--- a/src/rp2040/hardware_regs/include/hardware/regs/pio.h
+++ b/src/rp2040/hardware_regs/include/hardware/regs/pio.h
@@ -378,7 +378,8 @@
 // =============================================================================
 // Register    : PIO_DBG_PADOUT
 // Description : Read to sample the pad output values PIO is currently driving
-//               to the GPIOs.
+//               to the GPIOs. On RP2040 there are 30 GPIOs, so the two most
+//               significant bits are hardwired to 0.
 #define PIO_DBG_PADOUT_OFFSET _u(0x0000003c)
 #define PIO_DBG_PADOUT_BITS   _u(0xffffffff)
 #define PIO_DBG_PADOUT_RESET  _u(0x00000000)
@@ -388,7 +389,8 @@
 // =============================================================================
 // Register    : PIO_DBG_PADOE
 // Description : Read to sample the pad output enables (direction) PIO is
-//               currently driving to the GPIOs.
+//               currently driving to the GPIOs. On RP2040 there are 30 GPIOs,
+//               so the two most significant bits are hardwired to 0.
 #define PIO_DBG_PADOE_OFFSET _u(0x00000040)
 #define PIO_DBG_PADOE_BITS   _u(0xffffffff)
 #define PIO_DBG_PADOE_RESET  _u(0x00000000)
diff --git a/src/rp2040/hardware_regs/include/hardware/regs/xosc.h b/src/rp2040/hardware_regs/include/hardware/regs/xosc.h
index 4af78b9..ecc1096 100644
--- a/src/rp2040/hardware_regs/include/hardware/regs/xosc.h
+++ b/src/rp2040/hardware_regs/include/hardware/regs/xosc.h
@@ -128,7 +128,8 @@
 // -----------------------------------------------------------------------------
 // Field       : XOSC_STARTUP_X4
 // Description : Multiplies the startup_delay by 4. This is of little value to
-//               the user given that the delay can be programmed directly
+//               the user given that the delay can be programmed directly. Set
+//               to 0 at reset.
 #define XOSC_STARTUP_X4_RESET  "-"
 #define XOSC_STARTUP_X4_BITS   _u(0x00100000)
 #define XOSC_STARTUP_X4_MSB    _u(20)
@@ -136,7 +137,8 @@
 #define XOSC_STARTUP_X4_ACCESS "RW"
 // -----------------------------------------------------------------------------
 // Field       : XOSC_STARTUP_DELAY
-// Description : in multiples of 256*xtal_period
+// Description : in multiples of 256*xtal_period. Set to 0xc4 at reset (approx
+//               50 000 cycles)
 #define XOSC_STARTUP_DELAY_RESET  "-"
 #define XOSC_STARTUP_DELAY_BITS   _u(0x00003fff)
 #define XOSC_STARTUP_DELAY_MSB    _u(13)
diff --git a/src/rp2040/hardware_regs/rp2040.svd b/src/rp2040/hardware_regs/rp2040.svd
index f600d47..4b6ec19 100644
--- a/src/rp2040/hardware_regs/rp2040.svd
+++ b/src/rp2040/hardware_regs/rp2040.svd
@@ -22320,13 +22320,13 @@
             <field>
               <access>read-write</access>
               <bitRange>[20:20]</bitRange>
-              <description>Multiplies the startup_delay by 4. This is of little value to the user given that the delay can be programmed directly</description>
+              <description>Multiplies the startup_delay by 4. This is of little value to the user given that the delay can be programmed directly. Set to 0 at reset.</description>
               <name>X4</name>
             </field>
             <field>
               <access>read-write</access>
               <bitRange>[13:0]</bitRange>
-              <description>in multiples of 256*xtal_period</description>
+              <description>in multiples of 256*xtal_period. Set to 0xc4 at reset (approx 50 000 cycles)</description>
               <name>DELAY</name>
             </field>
           </fields>
@@ -42112,14 +42112,14 @@
         <register>
           <access>read-only</access>
           <addressOffset>0x003c</addressOffset>
-          <description>Read to sample the pad output values PIO is currently driving to the GPIOs.</description>
+          <description>Read to sample the pad output values PIO is currently driving to the GPIOs. On RP2040 there are 30 GPIOs, so the two most significant bits are hardwired to 0.</description>
           <name>DBG_PADOUT</name>
           <resetValue>0x00000000</resetValue>
         </register>
         <register>
           <access>read-only</access>
           <addressOffset>0x0040</addressOffset>
-          <description>Read to sample the pad output enables (direction) PIO is currently driving to the GPIOs.</description>
+          <description>Read to sample the pad output enables (direction) PIO is currently driving to the GPIOs. On RP2040 there are 30 GPIOs, so the two most significant bits are hardwired to 0.</description>
           <name>DBG_PADOE</name>
           <resetValue>0x00000000</resetValue>
         </register>