Download the Samsung firmware for the Galaxy J7 Duo SM-J720M with product code CHO from Chile. This firmware has version number PDA J720MUBU1ARD6 and CSC J720MOWO1ARD6. The operating system of this firmware is Android 8.0.0 , with build date Wed, 25 Apr 2018 12:32:54 +0000. Security patch date is 2018-04-01, with changelist 13501552.
AP (System &Recovery)
BL (Bootloader)
CP (Modem / Radio)
CSC_*** (Country / Region / Operator)
HOME_CSC_*** (Country / Region / Operator)
Other options in case first option did not work or isn't possible.
Option 2 VOLUME DOWN + VOLUME UP then USB cable
Option 3 POWER + VOLUME DOWN + VOLUME UP
Option 4 POWER + VOLUME DOWN + HOME BUTTON
Option 5 (Note9) USB cable + VOLUME DOWN + BIXBY
Option 6 (Note10) POWER + VOLUME UP
AP (System &Recovery)
Other options in case first option did not work or isn't possible.
Option 2 VOLUME DOWN + VOLUME UP then USB cable
Option 3 POWER + VOLUME DOWN + VOLUME UP
Option 4 POWER + VOLUME DOWN + HOME BUTTON
Option 5 (Note9) USB cable + VOLUME DOWN + BIXBY
Option 6 (Note10) POWER + VOLUME UP
For most devices, the model number (e.g. "GT-I9505" or "SM-G900F") is found inside the device. It becomes visible when you open your device and remove the battery.
As an alternative, you can also type your model name (e.g. "GALAXY S5") instead of the number. But it may be a bit more difficult to find your specific device that way.
Still not sure? Then perhaps Samsung can help you out with their model number lookup tool.