diff --git a/lib/usb_dfu.c b/lib/usb_dfu.c
index c1bd6c6..2c324ca 100644
--- a/lib/usb_dfu.c
+++ b/lib/usb_dfu.c
@@ -136,7 +136,7 @@ static void usb_disconnect(void)
 	gpio_set_output_options(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_2MHZ, GPIO12);
 	gpio_clear(GPIOA, GPIO12);
 	// USB disconnected must be at least 10 ms long, at most 100 ms
-	for (volatile uint32_t i = 0; i < 0x8000; i++);
+	for (volatile uint32_t i = 0; i < 0x2000; i++);
 }
 
 /** disconnect USB and perform system reset
@@ -361,7 +361,6 @@ void usb_dfu_setup(void)
 	}
 
 	rcc_periph_reset_pulse(RST_OTGFS); // reset USB peripheral
-	usb_disconnect(); // disconnect to force re-enumeration
 	rcc_periph_clock_enable(RCC_GPIOA); // enable clock for GPIO used for USB
 	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO11 | GPIO12); // set pin to alternate function
 	gpio_set_af(GPIOA, GPIO_AF10, GPIO11 | GPIO12); // set alternate function to USB