| Specification HTC U21 |
| Root HTC U21 |
| Unlock HTC U21 |
| Firmware HTC U21 |
| Developer Mode HTC U21 |
| Bypass Lock Screen HTC U21 |
| HTC U21 Factory Reset |
| Bypass FRP HTC U21 |
| Screenshot HTC U21 |
|
OS: Android v10 (Q) CPU: Qualcomm SDM765 Snapdragon 765G (7 nm) RAM: 8 GB Display: 6.8 inches Battery: 5000 mAh |
| *#06# | - IMEI (International Mobile Equipment Identity) number |
| *#*#3424#*#* | - Engineering Mode |
| *#*#3646633#*#* or *#*#54298#*#* | - Engineering Mode (for smartphones based on MTK processor) |
| *#*#4636#*#* | - Displaying Phone Information (Phone, Battery, WiFi and other) |
| *#*#225#*#* | - Calendar Storage, check your events in calendar |
| *#*#426#*#* | - Information about the connection with Google Play Services |
| *#0011# | - ServiceMode |
| *#0808# | - Change USB Settings |
| *#9900# | - Dump mode |
| *#9090# | - Diagnostic configuration |
| *#0*# | - General Test Mode |
| *#2663# | - TSP / TSK firmware update |
| *#12580*369# | - Software and hardware info |
| *#0283# | - Audio Loopback Control |
| #7465625*638*# | - Insert Network Lock Key Code |
| *#*#759#*#* | - RLZ Debug UI (Device ID, Activation Status, Some Ping Stuff, and few other things) |
| *#*#36245#*#* | - Email debug information |
| *#*#8255#*#* | - Used to launch G Talk Service Monitor |
| *#*#64663#*#* | - Hardware Test (Version, Sensors, Sim, WLAN, Bluetooth, Battery, OTG, Radio, Speakers) |
| *#*#7780#*#* | - Used for a factory data reset. |
| *2767*3855# | - Complete wiping of your mobile |
| *#*#232338#*#* | - Displays Wi-Fi Mac-address |
| *#*#34971539#*#* or *#34971539# | - Shows complete camera information |
| *#*#1234#*#* | - PDA and Phone firmware info |
| *#*#7594#*#* | - Changing the power button behavior-Enables direct poweroff once the code enabled |
| *#*#1472365#*#* | - For a quick GPS test |
| *#*#273283*255*663282*#*#* | - For a quick backup to all your media files |
| *#*#1575#*#* | - Different GPS Test Code |
| *#*#197328640#*#* | - Enabling test mode for service activity |
| *#*#0283#*#* | - Packet Loopback test |
| *#0228# | - battery calibration |
| *#*#232339#*#* OR *#*#526#*#* | - Wireless Lan Tests |
| *#*#0*#*#* | - LCD display test Code |
| *#*#3264#*#* | - See Ram version |
| *#*#1111#*#* | - FTA Software version |
| *#*#2664#*#* | - Touch-Screen test |
| *#*#0588#*#* | - Proximity sensor test |
| *#*#8351#*#* | - Enables voice dialing logging mode |
| *#*#232331#*#* | - Bluetooth Test Mode |
| *#*#232337#*# | - Displays bluetooth device address |
| *#*#7262626#*#* | - Field test |
| *#*#0289#*#* OR *#*#0673#*#* | - Audio test |
| *#*#0842#*#* | - Device test (vibration test and backlight test) |
| *#*#2663#*#* | - Display device's touch-screen version |
| *#*#44336#*#* | - Displays Build time and change list number |
| *#*#4986*2650468#*#* | - PDA, Phone, Hardware, RF Call Date firmware info |
| *#*#8350#*#* | - Disables voice dialing logging mode |
| *#*#2222#*#* | - FTA Hardware verion |
| Change code | |
| **03*old code*new code*new code# | |
| - Change code for call barring | |
| **04*old PIN code*new PIN *new PIN# | |
| - Change SIM Card PIN code | |
| **042*old PIN2 code*new PIN2*new PIN2# | |
| - Change SIM Card PIN2 code | |
| **05*PUK code*new PUK*new PUK# | |
| - Change SIM Card PUK code | |
| **052*PUK2 code*new PUK2*new PUK2# | |
| - Change SIM Card PUK2 code | |
| Call waiting | |
| *43# | - Activate call waiting |
| #43# | - Deactivate call waiting |
| *#43# | - Check status of call waiting |
| USSD Codes For Call Forwarding | |
| ##002# | - Disable All Call Forwarding |
| **004*PhoneNumber# | - Set all configured call diversions to PhoneNumber |
| ##004# | - Unregister all configured call diversions |
| Call Forward All | |
| *21*PhoneNumber# | - Register and activate divert all calls to PhoneNumber |
| ##21# | - Unregister divert all calls |
| *21# | - Enable Divert all calls on your phone |
| #21# | - Disable Divert all calls on your phone |
| *#21# | - Check status of divert all calls |
| Set call forwarding in case of "no answer" | |
| **61*PhoneNumber# | - Register and activate divert on no answer to PhoneNumber |
| ##61# | - Unregister divert on no answer |
| *61# | - Activate divert on no answer calls |
| #61# | - Deactivate divert on no answer calls |
| *#61# | - Check status of divert on no answer |
| Call diversion when "not available" | |
| **62*PhoneNumber# | - Register and activate divert on not reachable |
| ##62# | - Unregister divert on not reachable |
| *62# | - Activate divert on not reachable |
| #62# | - Deactivate divert on not reachable |
| *#62# | - Check status of divert on not reachable |
| Diversion in case of "busy" | |
| **67*PhoneNumber# | - Register and activate divert on busy |
| ##67# | - Unregister divert on busy |
| *67# | - Activate divert on busy |
| #67# | - Deactivate divert on busy |
| *#67# | - Check status of divert on busy all call types |
| *#67*11# | - Check status of divert on busy voice calls |
| *#67*13# | - Check status of divert on busy fax calls |
| *#67*25# | - Check status of divert on busy data calls |
| Set barring of all outgoing calls | |
| **33*code# | - Activate barr all outgoing calls (for code see "Safety" above) |
| #33*code# | - Deactivate barr all outgoing calls |
| *#33# | - Check status of barr all outgoing calls |
| Blocking all calls | |
| **330*code# | - Activate all calls barring |
| #330*code# | - Deactivate all calls barring |
| *#330*code# | - Check status of barr all calls |
| USSD Codes For Barring all outgoing international calls | |
| **331*code# | - To turn Barring On for all outgoing international calls |
| #331*code# | - To turn Barring OFF for all outgoing international calls |
| *#331*code# | - Check status of barr all outgoing international calls |
| Activate barr all outgoing international calls except home country | |
| **332*code# | - Enable Barr all outgoing international calls except home country on your phone |
| #332*code# | - Disable Barr all outgoing international calls except home country on your phone |
| *#332*code# | - Check status of barr all outgoing international calls except home country |
| Blocking all outgoing calls | |
| **333*code# | - To turn Barring On for all outgoing calls |
| #333*code# | - To turn Barring OFF for all outgoing calls |
| *#333# | - Check status of barr all outgoing calls |
| Set barring of all incoming calls | |
| **35*code# | - Activate all incoming calls barring |
| #35*code# | - Deactivate all incoming calls barring |
| *#35# | - Check status of barr all incoming calls |
| Blocking all incoming calls when roaming | |
| **351*code# | - Activate all incoming calls when roaming barring |
| #351*code# | - Deactivate all incoming calls when roaming barring |
| *#351# | - Check status of barr all incoming calls when roaming |
| USSD Codes For Barring all incoming calls | |
| **353*code# | - Activate Blocking all incoming calls |
| #353*code# | - Deactivate Blocking all incoming calls |
| *#353# | - Check status of Blocking all incoming calls |
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Thomas Nilan Smartphone Expert |
| Thomas Nilan is a mobile phone expert with in-depth knowledge of the Android and iOS operating systems, who understands the settings of various hidden features that allow you to expand the capabilities of your smartphone, as well as get information about what is going on inside the phone for future repairs. He is an authority in his field, which has allowed him to become a ghostwriter for several technology publications, and he enjoys writing small mobile applications for testing smartphones. | |
 | Qlbaned | March 30, 2024 |
| The Android v10 operating system provides a smooth user experience with excellent performance. The camera takes high-quality photos, and the battery life is impressive. Great value for money. | ||
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