Index: firmware/kernel.c
===================================================================
--- firmware/kernel.c	(revision 31209)
+++ firmware/kernel.c	(working copy)
@@ -1214,7 +1214,7 @@
     corelock_unlock(&s->cl);
     restore_irq(oldlevel);
 
-#if defined(HAVE_PRIORITY_SCHEDULING) && defined(irq_enabled_checkval)
+#if 0 //defined(HAVE_PRIORITY_SCHEDULING) && defined(irq_enabled_checkval)
     /* No thread switch if IRQ disabled - it's probably called via ISR.
      * switch_thread would as well enable them anyway. */
     if((result & THREAD_SWITCH) && irq_enabled_checkval(oldlevel))
Index: firmware/target/arm/crt0.S
===================================================================
--- firmware/target/arm/crt0.S	(revision 31209)
+++ firmware/target/arm/crt0.S	(working copy)
@@ -100,17 +100,17 @@
     strhi   r4, [r2], #4
     bhi     1b
 
-    /* Set up stack for IRQ mode */ 
+    /* Set up stack for IRQ mode */
     msr     cpsr_c, #0xd2
     ldr     sp, =irq_stack
-
-    /* Set up stack for FIQ mode */ 
+#if 0
+    /* Set up stack for FIQ mode */
     msr     cpsr_c, #0xd1
     ldr     sp, =fiq_stack
-
+#endif
     /* Let svc, abort and undefined modes use irq stack */
     msr     cpsr_c, #0xd3
-    ldr     sp, =irq_stack
+    ldr     sp, =svc_stack
     msr     cpsr_c, #0xd7
     ldr     sp, =irq_stack
     msr     cpsr_c, #0xdb
@@ -159,7 +159,7 @@
     b      UIE
 
 data_abort_handler:
-    sub    r0, lr, #8 
+    sub    r0, lr, #8
     mov    r1, #2
     b      UIE
 
@@ -169,5 +169,5 @@
 
 /* 256 words of FIQ stack */
     .space 256*4
-fiq_stack:
+svc_stack:
 end:
Index: firmware/target/arm/as3525/ascodec-as3525.c
===================================================================
--- firmware/target/arm/as3525/ascodec-as3525.c	(revision 31209)
+++ firmware/target/arm/as3525/ascodec-as3525.c	(working copy)
@@ -161,7 +161,7 @@
     while (i2c_busy());
 
     /* disable clock - already in IRQ context */
-    CGU_PERI &= ~CGU_I2C_AUDIO_MASTER_CLOCK_ENABLE;
+    bitclr32(&CGU_PERI, CGU_I2C_AUDIO_MASTER_CLOCK_ENABLE);
 
     req->status = 1;
 
@@ -339,7 +339,10 @@
 
 static void ascodec_wait(struct ascodec_request *req)
 {
-    if (irq_enabled()) {
+    unsigned long value;
+    asm volatile ("mrs %0, cpsr\n" : "=r"(value));
+
+    if ((value & 0x1f) == 0x1f && irq_enabled()) {
         semaphore_wait(&req->complete, TIMEOUT_BLOCK);
         return;
     }
Index: firmware/target/arm/as3525/sansa-fuzev2/button-fuzev2.c
===================================================================
--- firmware/target/arm/as3525/sansa-fuzev2/button-fuzev2.c	(revision 31209)
+++ firmware/target/arm/as3525/sansa-fuzev2/button-fuzev2.c	(working copy)
@@ -78,10 +78,17 @@
 
     unsigned int btn = BUTTON_NONE;
 
-    if (old_wheel_value == wheel_tbl[0][wheel_value])
+    if (hold_button)
+    {
+    }
+    else if (old_wheel_value == wheel_tbl[0][wheel_value])
+    {
         btn = BUTTON_SCROLL_FWD;
+    }
     else if (old_wheel_value == wheel_tbl[1][wheel_value])
+    {
         btn = BUTTON_SCROLL_BACK;
+    }
 
     if (btn == BUTTON_NONE)
     {
@@ -225,8 +232,10 @@
     int delay = 30;
     while(delay--) nop;
 
+    int oldlevel = disable_irq_save();
+
     bool ccu_io_bit12 = CCU_IO & (1<<12);
-    bitclr32(&CCU_IO, 1<<12);
+    CCU_IO &= ~(1<<12);
 
     /* B1 is shared with FM i2c */
     bool gpiob_pin0_dir = GPIOB_DIR & (1<<1);
@@ -256,8 +265,10 @@
         GPIOB_DIR |= 1<<1;
 
     if(ccu_io_bit12)
-        bitset32(&CCU_IO, 1<<12);
+        CCU_IO |= (1<<12);
 
+    restore_irq(oldlevel);
+
 #ifdef HAS_BUTTON_HOLD
 #ifndef BOOTLOADER
     /* light handling */
@@ -265,12 +276,6 @@
     {
         hold_button = hold;
         backlight_hold_changed(hold);
-        /* mask scrollwheel irq so we don't need to check for
-         * the hold button in the isr */
-        if (hold)
-            GPIOA_IE &= ~SCROLLWHEEL_BITS;
-        else
-            GPIOA_IE |= SCROLLWHEEL_BITS;
     }
 #else
     hold_button = hold;