[Samsung Galaxy A20 Questions & Answers] sercari:
Thanks to TBM13 from the telegram @Galaxy_A20_official group who shared with me the list of files and directories on their sec_efs partition.

Thanks to TOP who shared the list of files on his cpefs partition. Thanks to this I can continue investigating.

mmcblk0p4 (sec_efs):

.:
total 180
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 .
drwxr-xr-x 30 root root 0 2021-02-24 17:24 ..
drwxrwxr-x 2 radio system 4096 2019-01-01 12:00 Battery
drwxrwxr-x 3 system system 4096 2019-08-31 03:09 FactoryApp
drwxrwx--- 2 radio system 4096 2019-01-01 12:00 TEE
drwxr--r-- 2 system system 4096 2019-01-01 12:00 adp_token
drwx------ 2 system system 4096 2019-01-01 12:00 afc
drwxrwx--x 2 radio system 4096 2019-06-29 17:29 cpk
drwxrwxr-x 2 root radio 4096 2020-04-29 04:04 imei
drwx------ 2 root root 16384 2008-12-31 15:00 lost+found
drwxrwxr-x 2 system system 4096 2020-12-15 23:19 lpm
-rw-rw---- 1 root system 256 2020-12-15 23:19 lpm_boot.log
drwx------ 2 nfc nfc 4096 2019-01-01 12:00 nfc
drwxrwx--- 2 system audio 4096 2019-01-01 12:00 nxp
drwxrw---- 2 oem_5279 oem_5279 4096 2019-01-01 12:00 pfw_data
drwxrwx--- 2 system system 4096 2019-06-29 17:22 prov
drwxrwx--- 2 radio system 4096 2019-01-01 12:00 prov_data
drwxrwx--x 2 radio system 4096 2020-12-15 23:25 recovery
drwxrwxr-x 4 radio system 4096 2020-12-15 23:32 sec_efs
drwxrwx--- 2 system system 4096 2019-01-01 12:00 ssm
drwx------ 2 system system 4096 2019-01-01 12:00 tee
drwx------ 2 system system 4096 2019-08-31 01:46 umc
-rw-r--r-- 1 system system 168 2019-06-29 17:22 wv.keys

./Battery:
total 20
drwxrwxr-x 2 radio system 4096 2019-01-01 12:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..
-rw-rw---- 1 system system 4 2021-02-21 02:58 batt_capacity_max

./FactoryApp:
total 132
drwxrwxr-x 3 system system 4096 2019-08-31 03:09 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..
-rw------- 1 system system 28 2019-06-29 08:37 HwParamBattQR
-rw------- 1 system system 4876 2019-06-29 17:22 HwParamData
-rw------- 1 system system 824 2019-06-29 17:22 HwPartInform
drwx------ 2 system system 4096 2019-01-01 12:00 Sensorinfo
-rw-r----- 1 system log 3 2019-01-01 12:00 asoc
-rwxr--r-- 1 system system 1 2019-01-01 12:00 baro_delta
-rw-r----- 1 system system 2 2020-12-15 22:43 batt_after_manufactured
-rw------- 1 system system 4 2021-02-23 14:39 batt_cable_count
-rw-r----- 1 system system 6 2020-12-15 22:57 batt_discharge_level
-rw------- 1 system system 62 2021-02-24 17:10 batt_temp_charge
-rw------- 1 system system 1 2019-01-01 12:00 cable_detect_count_octa
-rw-rw---- 1 system system 195 2021-02-23 15:31 cisd_data
-rw-rw---- 1 system system 20 2019-01-01 12:00 cisd_wc_data
-rwxr--r-- 1 system system 13 2019-01-01 12:00 control_no
-rw------- 1 system system 2 2020-11-28 14:37 earjack_count
-rwxr--r-- 1 system system 2 2019-06-29 17:22 factorymode
-rwxrwxr-x 1 system radio 4 2019-01-01 12:00 fdata
-rw------- 1 system system 30 2021-02-24 13:06 gyro_cal_data
-rwxrwxr-x 1 system radio 0 2018-12-31 17:00 hist_nv
-rwxr--r-- 1 system system 2 2019-06-29 17:22 keystr
-rw------- 1 system system 5 2019-10-12 21:38 max_current
-rw------- 1 system system 4 2020-01-19 20:53 max_temp
-rwxr--r-- 1 system system 5 2019-06-29 17:29 mdnie
-rw------- 1 system system 1 2019-06-29 17:29 mdnie_ver
-rwxr--r-- 1 system system 5 2019-01-01 12:00 prepay
-rw------- 1 system system 1 2019-06-29 17:22 rtc_status
-rwxr--r-- 1 system system 11 2019-06-29 17:22 serial_no
-rwxrwxr-x 1 system radio 2000 2018-12-31 17:00 test_nv

./FactoryApp/Sensorinfo:
total 40
drwx------ 2 system system 4096 2019-01-01 12:00 .
drwxrwxr-x 3 system system 4096 2019-08-31 03:09 ..
-rw------- 1 system system 21 2019-01-01 12:00 Accelerometer
-rw------- 1 system system 4 2019-01-01 12:00 Barometer
-rw------- 1 system system 17 2019-01-01 12:00 Gyroscope
-rw------- 1 system system 4 2019-01-01 12:00 Light
-rw------- 1 system system 19 2019-01-01 12:00 Magnetometer
-rw------- 1 system system 31 2019-01-01 12:00 Proximity

./TEE:
total 16
drwxrwx--- 2 radio system 4096 2019-01-01 12:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..

./adp_token:
total 16
drwxr--r-- 2 system system 4096 2019-01-01 12:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..

./afc:
total 16
drwx------ 2 system system 4096 2019-01-01 12:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..

./cpk:
total 20
drwxrwx--x 2 radio system 4096 2019-06-29 17:29 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..
-rw-r--r-- 1 radio radio 920 2019-06-29 17:29 h2k.dat

./imei:
total 40
drwxrwxr-x 2 root radio 4096 2020-04-29 04:04 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..
-rw------- 1 root root 96 2021-02-21 03:41 factory.prop
-rwxrwxr-x 1 radio system 3 2020-12-15 23:26 mps_code.dat
-rw-rw-r-- 1 radio root 3 2020-12-15 23:26 omcnw_code.dat
-rw-rw-r-- 1 radio root 3 2020-12-15 23:26 omcnw_code2.dat
-rwxrwxr-x 1 system radio 14 2019-06-29 17:22 prodcode.dat
-rw-rw-r-- 1 system system 4 2019-12-29 20:07 total_call_time

./lost+found:
total 28
drwx------ 2 root root 16384 2008-12-31 15:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..

./lpm:
total 20
drwxrwxr-x 2 system system 4096 2020-12-15 23:19 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..
-rw-rw---- 1 root system 85 2020-12-15 23:19 lpm_info.log

./nfc:
total 16
drwx------ 2 nfc nfc 4096 2019-01-01 12:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..

./nxp:
total 16
drwxrwx--- 2 system audio 4096 2019-01-01 12:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..

./pfw_data:
total 16
drwxrw---- 2 oem_5279 oem_5279 4096 2019-01-01 12:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..

./prov:
total 20
drwxrwx--- 2 system system 4096 2019-06-29 17:22 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..
-rw----r-- 1 system system 559 2019-09-01 00:28 issued.log
-rw-rw---- 1 system system 0 2019-01-01 12:00 libdevkm.lock

./prov_data:
total 16
drwxrwx--- 2 radio system 4096 2019-01-01 12:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..

./recovery:
total 24
drwxrwx--x 2 radio system 4096 2020-12-15 23:25 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..
-rw------- 1 root root 257 2020-12-15 23:25 extra_history
-rw------- 1 root root 2529 2020-12-15 23:25 history

./sec_efs:
total 76
-rw------- 1 system system 569 2020-12-15 23:12 !SVC
drwxrwxr-x 4 radio system 4096 2020-12-15 23:32 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..
-rwx------ 1 root radio 0 2019-06-29 17:07 .ffw
-rw------- 1 system system 569 2020-12-15 23:12 SVC
-rw------- 1 system system 6655 2020-12-15 23:32 SettingsBackup.json
drwx------ 2 nfc nfc 4096 2019-01-01 12:00 nfc
-rw------- 1 system system 1517 2019-06-29 17:22 skpm_FACTORY_OCF_ECC_P256
-rw------- 1 system system 983 2019-09-01 00:29 skpm_OTA_WB_FIDO_Bound_FP_ECC_P256
-rw------- 1 system system 4104 2019-08-31 02:43 skpm_OTA_WB_TA_Downloader_RSA_2048
-rw------- 1 system system 3941 2019-08-31 02:43 skpm_sk.dat
-rw------- 1 system system 4711 2019-09-01 00:29 skpm_supported_list
drwx------ 2 system system 4096 2019-01-01 12:00 ucm_ca_cert

./sec_efs/nfc:
total 16
drwx------ 2 nfc nfc 4096 2019-01-01 12:00 .
drwxrwxr-x 4 radio system 4096 2020-12-15 23:32 ..

./sec_efs/ucm_ca_cert:
total 16
drwx------ 2 system system 4096 2019-01-01 12:00 .
drwxrwxr-x 4 radio system 4096 2020-12-15 23:32 ..

./ssm:
total 16
drwxrwx--- 2 system system 4096 2019-01-01 12:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..

./tee:
total 16
drwx------ 2 system system 4096 2019-01-01 12:00 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..

./umc:
total 20
drwx------ 2 system system 4096 2019-08-31 01:46 .
drwxrwx--x 21 system radio 4096 2019-08-31 01:46 ..
-rw------- 1 system system 1 2019-08-31 01:46 BulkEnrollmentProfile

Observing the list compare weight, permissions, owner and group of each file in /lost+found and I was able to deduce which file was and give it the corresponding location and name.

The only file I am missing is: /sec_efs/skpm_OTA_WB_FIDO_Bound_FP_ECC_P256

Someone has any idea about this file, apparently it is a key but I don't know if the phone should generate it automatically or how to get it.

I add that you do not know that the skpm_sk.dat file is blank. if I have it with a hex editor it is full of zeros

Thanks