[Galaxy Note Pro 12.2 Android Development] ultraradical:
Ok guys, I'm trying to solve this problem of the GPS, but before I need to discard that there is not a problem with partitions modemst1 and modemst2. Unfortunately my computer does not want to work with fastboot (seems to be a problem with USB3 aparently, because it works with adb), so I need a volunter to test this:

Make a full backup of your MODEM partition. You must do this, just in case.

Once installed all your drivers, busybox, enabled adb in development options, etc, and check that "adb devices" in your PC works, do:

adb root
adb remount
adb shell
su
cp /etc/gps.conf /etc/gps.conf.old
nano /etc/gps.conf

Now delete everything there (with C^K) and insert this, which is the original gps.conf from the stock ROM:

#Uncommenting these urls would only enable
#the power up auto injection and force injection(test case).
XTRA_SERVER_1=http://xtrapath1.izatcloud.net/xtra2.bin
XTRA_SERVER_2=http://xtrapath2.izatcloud.net/xtra2.bin
XTRA_SERVER_3=http://xtrapath3.izatcloud.net/xtra2.bin

#Version check for XTRA
#DISABLE = 0
#AUTO = 1
#XTRA2 = 2
#XTRA3 = 3
XTRA_VERSION_CHECK=0

# Error Estimate
# _SET = 1
# _CLEAR = 0
ERR_ESTIMATE=0

#Test
NTP_SERVER=time.gpsonextra.net
#Asia
# NTP_SERVER=asia.pool.ntp.org
#Europe
# NTP_SERVER=europe.pool.ntp.org
#North America
# NTP_SERVER=north-america.pool.ntp.org

# DEBUG LEVELS: 0 - none, 1 - Error, 2 - Warning, 3 - Info
# 4 - Debug, 5 - Verbose
# If DEBUG_LEVEL is commented, Android's logging levels will be used
DEBUG_LEVEL = 4

# Intermediate position report, 1=enable, 0=disable
INTERMEDIATE_POS=0

# Below bit mask configures how GPS functionalities
# should be locked when user turns off GPS on Settings
# Set bit 0x1 if MO GPS functionalities are to be locked
# Set bit 0x2 if NI GPS functionalities are to be locked
# default - non is locked for backward compatibility
#GPS_LOCK = 0

# supl version 1.0
SUPL_VER=0x10000

# Emergency SUPL, 1=enable, 0=disable
SUPL_ES=0 # Sensor R&D : Non-SUPL ES should be default

#Choose PDN for Emergency SUPL
#1 - Use emergency PDN
#0 - Use regular SUPL PDN for Emergency SUPL
USE_EMERGENCY_PDN_FOR_EMERGENCY_SUPL=1

#SUPL_MODE is a bit mask set in config.xml per carrier by default.
#If it is uncommented here, this value will over write the value from
#config.xml.
#MSA=0X2
#MSB=0X1
SUPL_MODE=0x3 #Sensor R&D : Change default bit mask

# GPS Capabilities bit mask
# SCHEDULING = 0x01
# MSB = 0x02
# MSA = 0x04
# ON_DEMAND_TIME = 0x10
# GEOFENCE = 0x20
# default = ON_DEMAND_TIME | MSA | MSB | SCHEDULING | GEOFENCE
CAPABILITIES=0x37

# Accuracy threshold for intermediate positions
# less accurate positions are ignored, 0 for passing all positions
# ACCURACY_THRES=5000

################################
##### AGPS server settings #####
################################

# FOR SUPL SUPPORT, set the following
# SUPL_HOST=supl.host.com or IP
# SUPL_PORT=1234

# FOR C2K PDE SUPPORT, set the following
# C2K_HOST=c2k.pde.com or IP
# C2K_PORT=1234

# Bitmask of slots that are available
# for write/install to, where 1s indicate writable,
# and the default value is 0 where no slots
# are writable. For example, AGPS_CERT_WRITABLE_MASK
# of b1000001010 makes 3 slots available
# and the remaining 7 slots unwritable.
#AGPS_CERT_WRITABLE_MASK=0

####################################
# LTE Positioning Profile Settings
####################################
# 0: Enable RRLP on LTE(Default)
# 1: Enable LPP_User_Plane on LTE
# 2: Enable LPP_Control_Plane
# 3: Enable both LPP_User_Plane and LPP_Control_Plane
LPP_PROFILE = 0 # Sensor R&D : This will not be injected to MODEM

################################
# EXTRA SETTINGS
################################
# NMEA provider (1=Modem Processor, 0=Application Processor)
NMEA_PROVIDER=1
# Mark if it is a SGLTE target (1=SGLTE, 0=nonSGLTE)
SGLTE_TARGET=0

##################################################
# Select Positioning Protocol on A-GLONASS system
##################################################
# 0x1: RRC CPlane
# 0x2: RRLP UPlane
# 0x4: LLP Uplane
A_GLONASS_POS_PROTOCOL_SELECT = 0 # Sensor R&D : This will not be injected to MODEM

##################################################
# Delete only Ephemeris files
##################################################
#0 : off - default
#1 : on - Erase only eph files when we use 'delete aiding data' function.
DEL_EPH_ONLY = 0

Ok, now close the window terminal, reopen a new one and do:

adb reboot bootloader

Once rebooted, if your fastboot works:

fastboot erase modemst1
fastboot erase modemst2

Now reboot and test the GPS.

With those instructions, if GPS works, we have the solution.