SPLIT - Remove NO_USB_STARTUP_CHECK requirement for usb detection (#7053)

* Avoid NO_USB_STARTUP_CHECK - Disable USB as checks seem to enable it somehow

* Update quantum/split_common/split_util.c

Co-Authored-By: fauxpark <fauxpark@gmail.com>

* Also remove NO_USB_STARTUP_CHECK from vitamins_included/rev1

3 files changed, 6 insertions, 3 deletions

diff --git a/keyboards/handwired/splittest/teensy_2/config.h b/keyboards/handwired/splittest/teensy_2/config.h
index 2b5bcf8e9..7c092db30 100644
--- a/keyboards/handwired/splittest/teensy_2/config.h
+++ b/keyboards/handwired/splittest/teensy_2/config.h
@@ -29,5 +29,3 @@
 
 // teensy has vbus detection issues - use usb detection instead
 #define SPLIT_USB_DETECT
-// required for teensy slave otherwise it "locks up" during startup
-#define NO_USB_STARTUP_CHECK
diff --git a/keyboards/vitamins_included/rev1/config.h b/keyboards/vitamins_included/rev1/config.h
index a6f9c95fb..c4881db01 100644
--- a/keyboards/vitamins_included/rev1/config.h
+++ b/keyboards/vitamins_included/rev1/config.h
@@ -21,7 +21,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "config_common.h"
 
 #define SPLIT_USB_DETECT
-#define NO_USB_STARTUP_CHECK
 
 #define EE_HANDS
 #define SOFT_SERIAL_PIN D0
diff --git a/quantum/split_common/split_util.c b/quantum/split_common/split_util.c
index 8983861bc..5c548de05 100644
--- a/quantum/split_common/split_util.c
+++ b/quantum/split_common/split_util.c
@@ -32,6 +32,12 @@ bool waitForUsb(void) {
         }
         wait_ms(100);
     }
+
+#if defined(__AVR__)
+    // Avoid NO_USB_STARTUP_CHECK - Disable USB as the previous checks seem to enable it somehow
+    (USBCON &= ~(_BV(USBE) | _BV(OTGPADE)));
+#endif
+
     return false;
 }