diff --git a/drv/rcc.c b/drv/rcc.c
index e36fe45..aefe4e3 100644
--- a/drv/rcc.c
+++ b/drv/rcc.c
@@ -161,7 +161,7 @@ static void apply_speed_preset(void)
 	//restore sane values
 	apply_default_preset();
 
-	//try enabling HSE, fallback to HSI if HSE fails
+	//enable HSE
 	regs->CR.HSEON = 1;
 	for (uint32_t i=0; i<10000; ++i) {
 		__asm__("nop");
@@ -169,18 +169,19 @@ static void apply_speed_preset(void)
 	if (regs->CR.HSERDY == 0x1) {
 		regs->CFGR.PLLSCR = 1;
 	} else {
-		regs->CR.HSEON = 0;
+		apply_default_preset();
+		while (true);
 	}
 
-	//configure PLL, fallback to HSI if PLL fails
+	//configure PLL
 	regs->CFGR.PLLMUL = 0x7; //PLL x9
 	regs->CR.PLLON = 1;
 	for (uint32_t i=0; i<10000; ++i) {
 		__asm__("nop");
 	}
 	if (regs->CR.PLLRDY != 0x1) {
-		regs->CR.PLLON = 0;
-		return; //clock low enough, no need for prescalers
+		apply_default_preset();
+		while (true);
 	}
 
 	//configure prescalers