diff --git a/cores/rp2040/SerialUSB.cpp b/cores/rp2040/SerialUSB.cpp
index e69c66a04..d420a2e4c 100644
--- a/cores/rp2040/SerialUSB.cpp
+++ b/cores/rp2040/SerialUSB.cpp
@@ -39,6 +39,7 @@ extern void serialEvent() __attribute__((weak));
 #define USBD_CDC_IN_OUT_MAX_SIZE (64)
 
 
+
 SerialUSB::SerialUSB() {
 }
 
@@ -50,17 +51,26 @@ void SerialUSB::begin(unsigned long baud) {
     }
 
     USB.disconnect();
-    static uint8_t cdc_desc[TUD_CDC_DESC_LEN] = {
-        // Interface number, string index, protocol, report descriptor len, EP In & Out address, size & polling interval
-        TUD_CDC_DESCRIPTOR(0 /* placeholder*/, USB.registerString("Pico Serial"), _epIn = USB.registerEndpointIn(), USBD_CDC_CMD_MAX_SIZE, _epOut = USB.registerEndpointOut(), USB.registerEndpointIn(), USBD_CDC_IN_OUT_MAX_SIZE)
-    };
 
-    _id = USB.registerInterface(2, cdc_desc, sizeof(cdc_desc), 1, 0);
+    _epIn = USB.registerEndpointIn();
+    _epOut = USB.registerEndpointOut();
+    _epIn2 = USB.registerEndpointIn();
+    _strID = USB.registerString("Pico Serial");
+
+    _id = USB.registerInterface(2, _cb, (void *)this, TUD_CDC_DESC_LEN, 1, 0);
 
     USB.connect();
     _running = true;
 }
 
+// Need to define here so we don't have to include tusb.h in global header (causes problemw w/BT redefining things)
+void SerialUSB::interfaceCB(int itf, uint8_t *dst, int len) {
+    uint8_t desc[TUD_CDC_DESC_LEN] = {
+        TUD_CDC_DESCRIPTOR((uint8_t)itf, _strID, _epIn, USBD_CDC_CMD_MAX_SIZE, _epOut, _epIn2, USBD_CDC_IN_OUT_MAX_SIZE)
+    };
+    memcpy(dst, desc, len);
+};
+
 void SerialUSB::end() {
     if (_running) {
         USB.disconnect();
diff --git a/cores/rp2040/SerialUSB.h b/cores/rp2040/SerialUSB.h
index 57b4f7778..99d08889a 100644
--- a/cores/rp2040/SerialUSB.h
+++ b/cores/rp2040/SerialUSB.h
@@ -57,11 +57,16 @@ class SerialUSB : public arduino::HardwareSerial {
     void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts);
     void tud_cdc_line_coding_cb(uint8_t itf, void const *p_line_coding); // Can't use cdc_line_coding_t const* p_line_coding, TinyUSB and BTStack conflict when we include tusb.h + BTStack.h
 
+    // USB interface descriptor CB
+    void interfaceCB(int itf, uint8_t *dst, int len);
+
 private:
     bool _running = false;
     uint8_t _id;
     uint8_t _epIn;
     uint8_t _epOut;
+    uint8_t _epIn2;
+    uint8_t _strID;
 
     typedef struct {
         unsigned int rebooting : 1;
@@ -73,6 +78,10 @@ class SerialUSB : public arduino::HardwareSerial {
     SyntheticState _ss = { 0, 0, 0, 0, 115200};
 
     void checkSerialReset();
+
+    static void _cb(int itf, uint8_t *dst, int len, void *param) {
+        ((SerialUSB *)param)->interfaceCB(itf, dst, len);
+    }
 };
 
 extern SerialUSB Serial;
diff --git a/cores/rp2040/USB.cpp b/cores/rp2040/USB.cpp
index 8309fe808..36326edf7 100644
--- a/cores/rp2040/USB.cpp
+++ b/cores/rp2040/USB.cpp
@@ -91,11 +91,12 @@ void USBClass::unregisterEndpointOut(int ep) {
     _endpointOut |= (1 << (ep - 0x80));
 }
 
-uint8_t USBClass::addEntry(Entry **head, int interfaces, const uint8_t *descriptor, size_t len, int ordering, uint32_t vidMask) {
+uint8_t USBClass::addEntry(Entry **head, int interfaces, void (*cb)(int itf, uint8_t *dst, int len, void *param), const void *param, size_t len, int ordering, uint32_t vidMask) {
     static uint8_t id = 1;
 
     Entry *n = (Entry *)malloc(sizeof(Entry));
-    n->descriptor = descriptor;
+    n->cb = cb;
+    n->param = param;
     n->len = len;
     n->interfaces = interfaces;
     n->order = ordering;
@@ -163,7 +164,7 @@ uint8_t USBClass::findInterfaceID(unsigned int localid) {
 
 // Called by a HID device to register a report.  Returns the *local* ID which must be mapped to the HID report ID
 uint8_t USBClass::registerHIDDevice(const uint8_t *descriptor, size_t len, int ordering, uint32_t vidMask) {
-    return addEntry(&_hids, 0, descriptor, len, ordering, vidMask);
+    return addEntry(&_hids, 0, nullptr, (const void *)descriptor, len, ordering, vidMask);
 }
 
 void USBClass::unregisterHIDDevice(unsigned int localid) {
@@ -171,8 +172,8 @@ void USBClass::unregisterHIDDevice(unsigned int localid) {
 }
 
 // Called by an object at global init time to add a new interface (non-HID, like CDC or Picotool)
-uint8_t USBClass::registerInterface(int interfaces, const uint8_t *descriptor, size_t len, int ordering, uint32_t vidMask) {
-    return addEntry(&_interfaces, interfaces, descriptor, len, ordering, vidMask);
+uint8_t USBClass::registerInterface(int interfaces, void (*cb)(int itf, uint8_t *dst, int len, void *), void *param, size_t len, int ordering, uint32_t vidMask) {
+    return addEntry(&_interfaces, interfaces, cb, param, len, ordering, vidMask);
 }
 
 void USBClass::unregisterInterface(unsigned int localid) {
@@ -293,7 +294,7 @@ void USBClass::setupDescHIDReport() {
     uint8_t id = 1;
     h = _hids;
     while (h) {
-        memcpy(p, h->descriptor, h->len);
+        memcpy(p, h->param, h->len);
         // Need to update the report ID, a 2-byte value
         char buff[] = { HID_REPORT_ID(id) };
         memcpy(p + 6, buff, sizeof(buff));
@@ -340,12 +341,12 @@ void USBClass::setupUSBDescriptor() {
             // Interface number, string index, protocol, report descriptor len, EP In & Out address, size & polling interval
             TUD_HID_DESCRIPTOR(1 /* placeholder*/, 0, HID_ITF_PROTOCOL_NONE, hid_report_len, _hid_endpoint = USB.registerEndpointIn(), CFG_TUD_HID_EP_BUFSIZE, (uint8_t)usb_hid_poll_interval)
         };
-        _hid_interface = USB.registerInterface(1, hid_desc, sizeof(hid_desc), 10, 0);
+        _hid_interface = USB.registerInterface(1, simpleInterface, hid_desc, sizeof(hid_desc), 10, 0);
     }
 
 #ifdef ENABLE_PICOTOOL_USB
     uint8_t picotool_desc[] = { TUD_RPI_RESET_DESCRIPTOR(1, USB.registerString("Reset")) };
-    _picotool_itf_num = USB.registerInterface(1, picotool_desc, sizeof(picotool_desc), 100, 0);
+    _picotool_itf_num = USB.registerInterface(1, simpleInterface, picotool_desc, sizeof(picotool_desc), 100, 0);
 #endif
 
     usbd_desc_cfg_len = TUD_CONFIG_DESC_LEN; // Always have a config descriptor
@@ -361,19 +362,18 @@ void USBClass::setupUSBDescriptor() {
         TUD_CONFIG_DESCRIPTOR(1, interface_count, USB.registerString(""), usbd_desc_cfg_len, TUSB_DESC_CONFIG_ATT_REMOTE_WAKEUP, USBD_MAX_POWER_MA)
     };
 
-    // Allocate the "real" HID report descriptor
+    // Allocate the "real" report descriptor
     usbd_desc_cfg = (uint8_t *)malloc(usbd_desc_cfg_len);
     bzero(usbd_desc_cfg, usbd_desc_cfg_len);
 
-    // Now copy the descriptors
+    // Now copy the interface descriptors
     h = _interfaces;
     uint8_t *p = usbd_desc_cfg;
     memcpy(p, tud_cfg_desc, sizeof(tud_cfg_desc));
     p += sizeof(tud_cfg_desc);
     int id = 0;
     while (h) {
-        memcpy(p, h->descriptor, h->len);
-        p[2] = id; // Set the interface
+        h->cb(id, p, h->len, (void *)h->param);
         p += h->len;
         id += h->interfaces;
         h = h->next;
diff --git a/cores/rp2040/USB.h b/cores/rp2040/USB.h
index 83101f508..c8f05c4ab 100644
--- a/cores/rp2040/USB.h
+++ b/cores/rp2040/USB.h
@@ -39,7 +39,7 @@ class USBClass {
     void unregisterHIDDevice(unsigned int localid);
 
     // Called by an object at global init time to add a new interface (non-HID, like CDC or Picotool)
-    uint8_t registerInterface(int interfaces, const uint8_t *descriptor, size_t len, int ordering, uint32_t vidMask);
+    uint8_t registerInterface(int interfaces, void (*cb)(int itf, uint8_t *dst, int len, void *param), void *param, size_t len, int ordering, uint32_t vidMask);
 
     // Remove a USB interface from the USB descriptor.  Only call after usbDisconnect or results could be unpredictable!
     void unregisterInterface(unsigned int localid);
@@ -94,6 +94,12 @@ class USBClass {
     uint8_t usbTaskIRQ;
 #endif
 
+    // Simple 1-interface updated for "easy" interfaces like Picotool or HIF
+    static void simpleInterface(int itf, uint8_t *dst, int len, void *data) {
+        memcpy(dst, data, len);
+        dst[2] = itf; // Set the interface
+    }
+
 private:
     // We can't use non-trivial variables to hold the hid, interface, or string lists.  The global
     // initialization where things like the global Keyboard may be called before the non-trivial
@@ -101,7 +107,8 @@ class USBClass {
 
     // Either a USB interface or HID device descriptor, kept in a linked list
     typedef struct Entry {
-        const uint8_t *descriptor;
+        void (*cb)(int itf, uint8_t *dst, int len, void *data); // unused for HID, only the report ID needs updating and we can do that inline
+        const void *param; // CB param or HID descriptor
         unsigned int len        : 12;
         unsigned int interfaces : 4;
         unsigned int order      : 18;
@@ -111,7 +118,7 @@ class USBClass {
     } Entry;
 
     // Add or remove Entry in a linked list, keeping things ordered by ordering
-    uint8_t addEntry(Entry **head, int interfaces, const uint8_t *descriptor, size_t len, int ordering, uint32_t vidMask);
+    uint8_t addEntry(Entry **head, int interfaces, void (*cb)(int itf, uint8_t *dst, int len, void *param), const void *param, size_t len, int ordering, uint32_t vidMask);
     void removeEntry(Entry **head, unsigned int localid);
 
     // Find the index (HID report ID or USB interface) of a given localid
@@ -124,7 +131,6 @@ class USBClass {
     // Gets a pointer to the HID report structure, optionally returning the size in len
     uint8_t *getDescHIDReport(int *len);
 
-private:
     Entry *_hids = nullptr;
     Entry *_interfaces = nullptr;
 
diff --git a/libraries/FatFSUSB/src/FatFSUSB.cpp b/libraries/FatFSUSB/src/FatFSUSB.cpp
index ad7cfd452..4520b34fa 100644
--- a/libraries/FatFSUSB/src/FatFSUSB.cpp
+++ b/libraries/FatFSUSB/src/FatFSUSB.cpp
@@ -63,7 +63,7 @@ bool FatFSUSBClass::begin() {
     _epIn = USB.registerEndpointIn();
     _epOut = USB.registerEndpointOut();
     static uint8_t msd_desc[] = { TUD_MSC_DESCRIPTOR(1 /* placeholder */, 0, _epOut, _epIn, USBD_MSC_EPSIZE) };
-    _id = USB.registerInterface(2, msd_desc, sizeof(msd_desc), 2, 0);
+    _id = USB.registerInterface(1, USBClass::simpleInterface, msd_desc, sizeof(msd_desc), 2, 0);
     USB.connect();
 
     _started = true;
diff --git a/libraries/SingleFileDrive/src/SingleFileDrive.cpp b/libraries/SingleFileDrive/src/SingleFileDrive.cpp
index 6fd9884e1..116317f90 100644
--- a/libraries/SingleFileDrive/src/SingleFileDrive.cpp
+++ b/libraries/SingleFileDrive/src/SingleFileDrive.cpp
@@ -61,7 +61,7 @@ bool SingleFileDrive::begin(const char *localFile, const char *dosFile) {
     _epIn = USB.registerEndpointIn();
     _epOut = USB.registerEndpointOut();
     static uint8_t msd_desc[] = { TUD_MSC_DESCRIPTOR(1 /* placeholder */, 0, _epOut, _epIn, USBD_MSC_EPSIZE) };
-    _id = USB.registerInterface(2, msd_desc, sizeof(msd_desc), 2, 0);
+    _id = USB.registerInterface(1, USBClass::simpleInterface, msd_desc, sizeof(msd_desc), 2, 0);
     USB.connect();
     _localFile = strdup(localFile);
     _dosFile = strdup(dosFile);