diff --git a/arm11/source/main.c b/arm11/source/main.c
index 99923892..e3904b25 100644
--- a/arm11/source/main.c
+++ b/arm11/source/main.c
@@ -195,6 +195,28 @@ static void deinitScreens(void)
     *(vu32 *)0x10202014 = 0;
 }
 
+static void zerofillN3dsAblRegisters(void)
+{
+    // It should be fine to write to these regs even on O3DS as they
+    // are RAZ/WI
+
+    // TODO: read from calibration, but null values should do just
+    // fine. From testing, LUT explicitly ignores null values, and
+    // it is probably the case of reg @ 0x54 as well.
+    *(vu32 *)0x10202250 = 0; // unknown 24-bit value, seen: 0
+    *(vu32 *)0x10202254 = 0; // unknown 24-bit value, seen: nonzero
+
+    *(vu32 *)0x10202A50 = 0; // unknown 24-bit value, seen: 0
+    *(vu32 *)0x10202A54 = 0; // unknown 24-bit value, seen: nonzero
+
+    for (u32 i = 0; i < 64; i++) {
+        // Blend colors (w/ color multiplication) for each group
+        // of 4 relative-luminance Rs
+        *(vu32 *)(0x10202300 + 4*i) = 0;
+        *(vu32 *)(0x10202B00 + 4*i) = 0;
+    }
+}
+
 void main(void)
 {
     operation = ARM11_READY;
@@ -223,6 +245,9 @@ void main(void)
             case DEINIT_SCREENS:
                 deinitScreens();
                 break;
+            case ZEROFILL_N3DS_ABL_REGISTERS:
+                zerofillN3dsAblRegisters();
+                break;
             case PREPARE_ARM11_FOR_FIRMLAUNCH:
                 memcpy((void *)0x1FFFFC00, (void *)prepareForFirmlaunch, prepareForFirmlaunchSize);
                 *(vu32 *)0x1FFFFFFC = 0;
diff --git a/arm11/source/types.h b/arm11/source/types.h
index 43eacc92..551b7d93 100644
--- a/arm11/source/types.h
+++ b/arm11/source/types.h
@@ -60,6 +60,7 @@ typedef enum
     SWAP_FRAMEBUFFERS,
     UPDATE_BRIGHTNESS,
     DEINIT_SCREENS,
+    ZEROFILL_N3DS_ABL_REGISTERS,
     PREPARE_ARM11_FOR_FIRMLAUNCH,
     ARM11_READY,
 } Arm11Operation;
diff --git a/arm9/source/deliver_arg.c b/arm9/source/deliver_arg.c
index 0ef1a596..d360e616 100644
--- a/arm9/source/deliver_arg.c
+++ b/arm9/source/deliver_arg.c
@@ -30,6 +30,7 @@
 #include "config.h"
 #include "fs.h"
 #include "i2c.h"
+#include "screen.h"
 
 u8 *loadDeliverArg(void)
 {
@@ -200,6 +201,29 @@ static bool configureHomebrewAutobootTwl(u8 *deliverArg)
 
     *(u16 *)(tlnc + 6) = crc16(tlnc + 8, 0x18, 0xFFFF);
 
+    // Even though (when running TWL/AGB FIRM) the SoC is in O3DS mode, and the GPU also is,
+    // as well as most other components behaving as such (external RAM, L2C not usable, etc.),
+    // this is NOT the case for the LCD and adaptive backlight logic which retains FULL N3DS
+    // functionality, including a feature where the window is blended with a given color depending
+    // on the overall relative luminance of that window.
+
+    // However, Nintendo's own code mistakenly assumes the opposite, and clearly so ("if GPU in N3DS mode"
+    // checks, not passing N3DS extra adaptive backlight (ABL) to TWL/AGB_FIRM). This has implications:
+
+    // - Powersaving (ABL) settings in TWL/AGB_FIRM is inconsistent with *both* O3DS (because the new RGB blend LUT
+    // has been set to its current value by NATIVE_FIRM) and N3DS (because "pwn_cnt" and "inertia" are missing
+    // their N3DS-only bits)
+    // - "rave party" when booting into TWL/AGB_FIRM or O3DS NATIVE_FIRM without these regs (well, the LUT) initialized.
+    // Easiest way to do so is by leveraging the "DSi autooboot" feature Luma provides. It is worth noting at least
+    // the LUT survives hardware reboots (if Nintendo were using DSi software that was using TLNC-based reboots,
+    // they wouldn't have noticed).
+
+    // As such, zerofill these registers (from testing, hardware explicitly discards null values, so this
+    // should be fine). For now, only touch the Luma-initiated autoboot path
+
+    if (ISN3DS)
+        zerofillN3dsAblRegisters();
+
     CFG_BOOTENV = 3;
 
     return true;
diff --git a/arm9/source/screen.c b/arm9/source/screen.c
index bb01525b..e82475d5 100644
--- a/arm9/source/screen.c
+++ b/arm9/source/screen.c
@@ -118,3 +118,8 @@ void initScreens(void)
     clearScreens(false);
     swapFramebuffers(false);
 }
+
+void zerofillN3dsAblRegisters(void)
+{
+    invokeArm11Function(ZEROFILL_N3DS_ABL_REGISTERS);
+}
\ No newline at end of file
diff --git a/arm9/source/screen.h b/arm9/source/screen.h
index 275ed686..01b21d1e 100644
--- a/arm9/source/screen.h
+++ b/arm9/source/screen.h
@@ -59,6 +59,7 @@ typedef enum
     SWAP_FRAMEBUFFERS,
     UPDATE_BRIGHTNESS,
     DEINIT_SCREENS,
+    ZEROFILL_N3DS_ABL_REGISTERS,
     PREPARE_ARM11_FOR_FIRMLAUNCH,
     ARM11_READY,
 } Arm11Operation;
@@ -73,3 +74,4 @@ void swapFramebuffers(bool isAlternate);
 void updateBrightness(u32 brightnessIndex);
 void clearScreens(bool isAlternate);
 void initScreens(void);
+void zerofillN3dsAblRegisters(void);