diff --git a/sepolicy/vendor/file.te b/sepolicy/vendor/file.te
index 799d7cb..e76b758 100644
--- a/sepolicy/vendor/file.te
+++ b/sepolicy/vendor/file.te
@@ -20,4 +20,5 @@ type sysfs_fuse, fs_type, sysfs_type;
 type sysfs_memplus, fs_type, sysfs_type;
 type sysfs_project_info, fs_type, sysfs_type;
 type sysfs_tpd, fs_type, sysfs_type;
+type sysfs_tri_state_key, sysfs_type, fs_type;
 type vendor_sysfs_video_call_on, fs_type, sysfs_type;
diff --git a/sepolicy/vendor/file_contexts b/sepolicy/vendor/file_contexts
index 5cfb89a..788edca 100644
--- a/sepolicy/vendor/file_contexts
+++ b/sepolicy/vendor/file_contexts
@@ -89,6 +89,7 @@
 # Sys files (wakeup)
 /sys/devices/platform/soc/c440000\.qcom,spmi/spmi-0/spmi0-00/c440000\.qcom,spmi:qcom,pm8150@0:qcom,pm8150_rtc/rtc/rtc0/wakeup[0-9]+(/.*)? u:object_r:sysfs_wakeup:s0
 /sys/devices/platform/soc/soc:oneplus_wlchg/power_supply/wireless/wakeup[0-9]+(/.*)? u:object_r:sysfs_wakeup:s0
+/sys/devices/platform/soc/soc:tri_state_key/hall_data_calib u:object_r:sysfs_tri_state_key:s0
 /sys/devices/virtual/diag/diag/wakeup[0-9]+(/.*)? u:object_r:sysfs_wakeup:s0
 /sys/devices/virtual/misc/msm_aac/wakeup[0-9]+(/.*)? u:object_r:sysfs_wakeup:s0
 /sys/devices/virtual/misc/msm_alac/wakeup[0-9]+(/.*)? u:object_r:sysfs_wakeup:s0
diff --git a/sepolicy/vendor/tri-state-key_daemon.te b/sepolicy/vendor/tri-state-key_daemon.te
index 08fdb5d..cdde618 100644
--- a/sepolicy/vendor/tri-state-key_daemon.te
+++ b/sepolicy/vendor/tri-state-key_daemon.te
@@ -5,3 +5,9 @@ init_daemon_domain(tri-state-key_daemon)
 
 allow tri-state-key_daemon uhid_device:chr_file rw_file_perms;
 allow tri-state-key_daemon self:netlink_kobject_uevent_socket create_socket_perms_no_ioctl;
+
+allow tri-state-key_daemon sysfs_tri_state_key:file w_file_perms;
+
+allow tri-state-key_daemon mnt_vendor_file:dir search;
+
+r_dir_file(tri-state-key_daemon, oem_file)
diff --git a/tri-state-key/main.cpp b/tri-state-key/main.cpp
index a721634..c3a3dfa 100644
--- a/tri-state-key/main.cpp
+++ b/tri-state-key/main.cpp
@@ -16,6 +16,7 @@
 
 #define LOG_TAG "tri-state-key_daemon"
 
+#include <android-base/file.h>
 #include <android-base/logging.h>
 #include <fcntl.h>
 #include <linux/input.h>
@@ -24,10 +25,15 @@
 
 #include "uevent_listener.h"
 
+#define HALL_CALIBRATION_DATA "/sys/devices/platform/soc/soc:tri_state_key/hall_data_calib"
+#define HALL_PERSIST_CALIBRATION_DATA "/mnt/vendor/persist/engineermode/tri_state_hall_data"
+
 #define KEY_MODE_NORMAL 601
 #define KEY_MODE_VIBRATION 602
 #define KEY_MODE_SILENCE 603
 
+using android::base::ReadFileToString;
+using android::base::WriteStringToFile;
 using android::Uevent;
 using android::UeventListener;
 
@@ -39,6 +45,11 @@ int main() {
 
     LOG(INFO) << "Started";
 
+    if (std::string hallData; ReadFileToString(HALL_PERSIST_CALIBRATION_DATA, &hallData)) {
+        std::replace(hallData.begin(), hallData.end(), ';', ',');
+        WriteStringToFile(hallData, HALL_CALIBRATION_DATA);
+    }
+
     uinputFd = open("/dev/uinput", O_WRONLY | O_NONBLOCK);
     if (uinputFd < 0) {
         LOG(ERROR) << "Unable to open uinput node";
diff --git a/tri-state-key/tri-state-key_daemon.rc b/tri-state-key/tri-state-key_daemon.rc
index 028d472..0886ab9 100644
--- a/tri-state-key/tri-state-key_daemon.rc
+++ b/tri-state-key/tri-state-key_daemon.rc
@@ -1,4 +1,7 @@
 on fs
+    chown system system /sys/devices/platform/soc/soc:tri_state_key/hall_data_calib
+    chown system system /mnt/vendor/persist/engineermode/tri_state_hall_data
+
     start tri-state-key_daemon
 
 service tri-state-key_daemon /vendor/bin/tri-state-key_daemon