Requirements:
1) Apktool 1.5.2
2) Notepad ++
3) SystemUI.apk
Procedure;
1) Decompile SystemUI.apk
2) Now goto decompiled folder and navigate to smali/com/android/systemui/statusbar/policy folder.
3) Open clock.smali using notepad++ and search for this method .method final updateClock()V and mark It until .end method
4) Replace it with this method
.method final updateClock()V
.locals 15
.prologue
const/4 v14, 0x0
.line 191
iget-object v11, p0, Lcom/android/systemui/statusbar/policy/Clock;->mCalendar:Ljava/util/Calendar;
invoke-static {}, Ljava/lang/System;->currentTimeMillis()J
move-result-wide v12
invoke-virtual {v11, v12, v13}, Ljava/util/Calendar;->setTimeInMillis(J)V
.line 200
invoke-virtual {p0}, Lcom/android/systemui/statusbar/policy/Clock;->getContext()Landroid/content/Context;
move-result-object v3
.line 201
.local v3, context:Landroid/content/Context;
invoke-static {v3}, Landroid/text/format/DateFormat;->is24HourFormat(Landroid/content/Context;)Z
move-result v2
.line 202
.local v2, b24:Z
const/4 v8, 0x0
.line 203
.local v8, res:I
const-string v1, ""
.line 205
.local v1, AM_PM:Ljava/lang/String;
if-nez v2, :cond_0
.line 206
iget-object v11, p0, Lcom/android/systemui/statusbar/policy/Clock;->mCalendar:Ljava/util/Calendar;
const/16 v12, 0x9
invoke-virtual {v11, v12}, Ljava/util/Calendar;->get(I)I
move-result v0
.line 207
.local v0, AMPM:I
if-nez v0, :cond_3
.line 208
const v8, 0x104009a
.line 214
.end local v0 #AMPM:I
:cond_0
:goto_0
if-eqz v8, :cond_1
.line 215
invoke-virtual {v3, v8}, Landroid/content/Context;->getString(I)Ljava/lang/String;
move-result-object v11
invoke-virtual {v11}, Ljava/lang/String;->toUpperCase()Ljava/lang/String;
move-result-object v1
.line 218
:cond_1
const v11, 0x7f0a005c
const/4 v12, 0x2
new-array v12, v12, [Ljava/lang/Object;
invoke-direct {p0}, Lcom/android/systemui/statusbar/policy/Clock;->getSmallTime()Ljava/lang/CharSequence;
move-result-object v13
aput-object v13, v12, v14
const/4 v13, 0x1
aput-object v1, v12, v13
invoke-virtual {v3, v11, v12}, Landroid/content/Context;->getString(I[Ljava/lang/Object;)Ljava/lang/String;
move-result-object v11
new-array v12, v14, [Ljava/lang/Object;
invoke-static {v11, v12}, Ljava/lang/String;->format(Ljava/lang/String;[Ljava/lang/Object;)Ljava/lang/String;
move-result-object v10
.line 221
.local v10, timeText:Ljava/lang/String;
if-eqz v8, :cond_4
sget-boolean v11, Lcom/android/systemui/statusbar/BaseStatusBar;->useTouchWizGUI:Z
if-eqz v11, :cond_4
sget-boolean v11, Lcom/android/systemui/statusbar/BaseStatusBar;->canStatusBarHide:Z
if-eqz v11, :cond_2
iget-boolean v11, p0, Lcom/android/systemui/statusbar/policy/Clock;->mExpandedHeader:Z
if-eqz v11, :cond_4
.line 223
:cond_2
new-instance v4, Landroid/text/SpannableStringBuilder;
invoke-direct {v4, v10}, Landroid/text/SpannableStringBuilder;-><init>(Ljava/lang/CharSequence;)V
.line 224
.local v4, formatted:Landroid/text/SpannableStringBuilder;
const/high16 v7, 0x3000
.line 225
.local v7, proportion:F
invoke-virtual {v10, v1}, Ljava/lang/String;->indexOf(Ljava/lang/String;)I
move-result v5
.line 226
.local v5, magic1:I
invoke-virtual {v1}, Ljava/lang/String;->length()I
move-result v6
.line 227
.local v6, magic2:I
new-instance v9, Landroid/text/style/RelativeSizeSpan;
invoke-direct {v9, v7}, Landroid/text/style/RelativeSizeSpan;-><init>(F)V
.line 228
.local v9, style:Landroid/text/style/CharacterStyle;
add-int v11, v5, v6
const/16 v12, 0x22
invoke-virtual {v4, v9, v5, v11, v12}, Landroid/text/SpannableStringBuilder;->setSpan(Ljava/lang/Object;III)V
.line 230
invoke-virtual {p0, v4}, Lcom/android/systemui/statusbar/policy/Clock;->setText(Ljava/lang/CharSequence;)V
.line 235
.end local v4 #formatted:Landroid/text/SpannableStringBuilder;
.end local v5 #magic1:I
.end local v6 #magic2:I
.end local v7 #proportion:F
.end local v9 #style:Landroid/text/style/CharacterStyle;
:goto_1
return-void
.line 210
.end local v10 #timeText:Ljava/lang/String;
.restart local v0 #AMPM:I
:cond_3
const v8, 0x104009b
goto :goto_0
.line 232
.end local v0 #AMPM:I
.restart local v10 #timeText:Ljava/lang/String;
:cond_4
invoke-virtual {p0, v10}, Lcom/android/systemui/statusbar/policy/Clock;->setText(Ljava/lang/CharSequence;)V
goto :goto_1
.end method
5) Now goto res/layout folder.
6) Open tw_status_bar.xml , tw_status_bar_dual.xml and tw_status_bar_expanded_header.xml
7) Search for code <com.android.systemui.statusbar.policy.clock
8) Add this attribute to it android:ampmSmall="true"
9) Save it , recompile it.
10) Sign it and push it to rw--rr
Credit: ShadeSk@xda