diff --git a/14-checkpoint/README.md b/14-checkpoint/README.md
index 8d9958e..7a04ed9 100644
--- a/14-checkpoint/README.md
+++ b/14-checkpoint/README.md
@@ -11,7 +11,9 @@ and think on a strategy.
 
 Take a look at the new folder structure. Most of the files have been symlinked
 from previous lessons, so if we have to change them at some point, it will be
-a better idea to remove the symlink and create a new file.
+a better idea to remove the symlink and create a new file. Open `boot/bootsect.asm`
+and note that since our kernel will be larger, the number of sectors to read when
+loading it from disk has increased from `2` to `16`.
 
 Furthermore, since from now on we will use mostly C to code, we'll take advantage of qemu's
 ability to open a connection to gdb. First, let's install a cross-compiled `gdb` since
diff --git a/14-checkpoint/boot/32bit_print.asm b/14-checkpoint/boot/32bit_print.asm
index 4169a17..e940aa9 100644
--- a/14-checkpoint/boot/32bit_print.asm
+++ b/14-checkpoint/boot/32bit_print.asm
@@ -2,7 +2,7 @@
 
 ; this is how constants are defined
 VIDEO_MEMORY equ 0xb8000
-WHITE_OB_BLACK equ 0x0f ; the color byte for each character
+WHITE_ON_BLACK equ 0x0f ; the color byte for each character
 
 print_string_pm:
     pusha
@@ -10,7 +10,7 @@ print_string_pm:
 
 print_string_pm_loop:
     mov al, [ebx] ; [ebx] is the address of our character
-    mov ah, WHITE_OB_BLACK
+    mov ah, WHITE_ON_BLACK
 
     cmp al, 0 ; check if end of string
     je print_string_pm_done
diff --git a/15-video-ports/boot/32bit_print.asm b/15-video-ports/boot/32bit_print.asm
index 4169a17..e940aa9 100644
--- a/15-video-ports/boot/32bit_print.asm
+++ b/15-video-ports/boot/32bit_print.asm
@@ -2,7 +2,7 @@
 
 ; this is how constants are defined
 VIDEO_MEMORY equ 0xb8000
-WHITE_OB_BLACK equ 0x0f ; the color byte for each character
+WHITE_ON_BLACK equ 0x0f ; the color byte for each character
 
 print_string_pm:
     pusha
@@ -10,7 +10,7 @@ print_string_pm:
 
 print_string_pm_loop:
     mov al, [ebx] ; [ebx] is the address of our character
-    mov ah, WHITE_OB_BLACK
+    mov ah, WHITE_ON_BLACK
 
     cmp al, 0 ; check if end of string
     je print_string_pm_done
diff --git a/16-video-driver/boot/32bit_print.asm b/16-video-driver/boot/32bit_print.asm
index 4169a17..e940aa9 100644
--- a/16-video-driver/boot/32bit_print.asm
+++ b/16-video-driver/boot/32bit_print.asm
@@ -2,7 +2,7 @@
 
 ; this is how constants are defined
 VIDEO_MEMORY equ 0xb8000
-WHITE_OB_BLACK equ 0x0f ; the color byte for each character
+WHITE_ON_BLACK equ 0x0f ; the color byte for each character
 
 print_string_pm:
     pusha
@@ -10,7 +10,7 @@ print_string_pm:
 
 print_string_pm_loop:
     mov al, [ebx] ; [ebx] is the address of our character
-    mov ah, WHITE_OB_BLACK
+    mov ah, WHITE_ON_BLACK
 
     cmp al, 0 ; check if end of string
     je print_string_pm_done
diff --git a/17-video-scroll/boot/32bit_print.asm b/17-video-scroll/boot/32bit_print.asm
index 4169a17..e940aa9 100644
--- a/17-video-scroll/boot/32bit_print.asm
+++ b/17-video-scroll/boot/32bit_print.asm
@@ -2,7 +2,7 @@
 
 ; this is how constants are defined
 VIDEO_MEMORY equ 0xb8000
-WHITE_OB_BLACK equ 0x0f ; the color byte for each character
+WHITE_ON_BLACK equ 0x0f ; the color byte for each character
 
 print_string_pm:
     pusha
@@ -10,7 +10,7 @@ print_string_pm:
 
 print_string_pm_loop:
     mov al, [ebx] ; [ebx] is the address of our character
-    mov ah, WHITE_OB_BLACK
+    mov ah, WHITE_ON_BLACK
 
     cmp al, 0 ; check if end of string
     je print_string_pm_done
diff --git a/18-interrupts/boot/32bit_print.asm b/18-interrupts/boot/32bit_print.asm
index 4169a17..e940aa9 100644
--- a/18-interrupts/boot/32bit_print.asm
+++ b/18-interrupts/boot/32bit_print.asm
@@ -2,7 +2,7 @@
 
 ; this is how constants are defined
 VIDEO_MEMORY equ 0xb8000
-WHITE_OB_BLACK equ 0x0f ; the color byte for each character
+WHITE_ON_BLACK equ 0x0f ; the color byte for each character
 
 print_string_pm:
     pusha
@@ -10,7 +10,7 @@ print_string_pm:
 
 print_string_pm_loop:
     mov al, [ebx] ; [ebx] is the address of our character
-    mov ah, WHITE_OB_BLACK
+    mov ah, WHITE_ON_BLACK
 
     cmp al, 0 ; check if end of string
     je print_string_pm_done
diff --git a/23-fixes/boot/32bit_print.asm b/23-fixes/boot/32bit_print.asm
index 4169a17..e940aa9 100644
--- a/23-fixes/boot/32bit_print.asm
+++ b/23-fixes/boot/32bit_print.asm
@@ -2,7 +2,7 @@
 
 ; this is how constants are defined
 VIDEO_MEMORY equ 0xb8000
-WHITE_OB_BLACK equ 0x0f ; the color byte for each character
+WHITE_ON_BLACK equ 0x0f ; the color byte for each character
 
 print_string_pm:
     pusha
@@ -10,7 +10,7 @@ print_string_pm:
 
 print_string_pm_loop:
     mov al, [ebx] ; [ebx] is the address of our character
-    mov ah, WHITE_OB_BLACK
+    mov ah, WHITE_ON_BLACK
 
     cmp al, 0 ; check if end of string
     je print_string_pm_done