[General Questions and Answers] optimusodd:
I extracted the Stock ROM zip and found it's updater script in "META-INF/com/google/android"

ifelse( getprop("ro.build.id") == "OPR1.170623.026", ui_print("Android O device"), (
(greater_than_int(getprop("ro.build.date.utc"), 1514390400)) || abort("Can't install this package on device version less than 14.2020.1712.85 device build time (" + getprop("ro.build.date") + ").");
) );
ifelse( getprop("ro.product.name") == "OPEN_Phone", ui_print("OPEN SKU device"), (
getprop("ro.product.name") == "WW_Phone" || abort("This package is for \"WW_Phone\" devices; this is a \"" + getprop("ro.product.name") + "\".");
) );
ui_print("Target: asus/WW_Phone/ASUS_Z012D:8.0.0/OPR1.170623.026/15.0410.1807.75-0:user/release-keys");
show_progress(0.750000, 540);
ui_print("Patching system image unconditionally...");
block_image_update("/dev/block/bootdevice/by-name/system", package_extract_file("system.transfer.list"), "system.new.dat", "system.patch.dat") ||
abort("E1001: Failed to update system image.");
ui_print("Verifying the updated system image...");
if range_sha1("/dev/block/bootdevice/by-name/system", "136,0,32767,32768,32770,33009,33011,33516,65535,65536,65538,66043,98303,98304,98306,98545,98547,99052,131071,131072,131074,131579,163839,163840,163842,164081,164083,164588,196607,196608,196610,197115,229375,229376,229378,229617,229619,230124,262143,262144,262146,262651,294910,294912,294914,295153,295155,295660,327679,327680,327682,328187,335068,360448,360450,360955,393214,393216,393218,393723,393724,393725,425982,425984,425986,426491,458751,458752,458754,459259,491519,491520,491522,492027,524287,524288,524290,524795,557055,557056,557058,557563,589823,589824,589826,590331,622591,622592,622594,623099,655358,655360,655362,655867,688126,688128,688130,688635,720894,720896,720898,721403,753662,753664,753666,754171,786430,786432,786434,786939,819198,819200,819202,819441,819443,819948,851966,851968,851970,852475,884734,884736,884738,884977,884979,885484,917502,917504,917506,918011,950270,950272,950274,950779,967696,967697,983040") == "9a4740126249131da4ccd7e39fcf8d7302a3f818" then
if range_sha1("/dev/block/bootdevice/by-name/system", "136,32767,32768,32770,33009,33011,33516,65535,65536,65538,66043,98303,98304,98306,98545,98547,99052,131071,131072,131074,131579,163839,163840,163842,164081,164083,164588,196607,196608,196610,197115,229375,229376,229378,229617,229619,230124,262143,262144,262146,262651,294910,294912,294914,295153,295155,295660,327679,327680,327682,328187,335068,335580,359936,360448,360450,360955,393214,393216,393218,393723,393724,393725,425982,425984,425986,426491,458751,458752,458754,459259,491519,491520,491522,492027,524287,524288,524290,524795,557055,557056,557058,557563,589823,589824,589826,590331,622591,622592,622594,623099,655358,655360,655362,655867,688126,688128,688130,688635,720894,720896,720898,721403,753662,753664,753666,754171,786430,786432,786434,786939,819198,819200,819202,819441,819443,819948,851966,851968,851970,852475,884734,884736,884738,884977,884979,885484,917502,917504,917506,918011,950270,950272,950274,950779,967696,967697") == "6d1cea242bbacf2ea86f62fa6c06b6bde31ec430" then
ui_print("Verified the updated system image.");
else
abort("E1003: system partition has unexpected non-zero contents after OTA update");
endif;
else
abort("E1002: system partition has unexpected contents after OTA update");
endif;
show_progress(0.050000, 5);
package_extract_file("boot.img", "/dev/block/bootdevice/by-name/boot");
show_progress(0.200000, 10);

# ---- radio update tasks ----

ui_print("Patching firmware images...");
ifelse(msm.boot_update("main"), (
ui_print("installing cmnlib64");
package_extract_s_file("firmware-update/cmnlib64.mbn", "/dev/block/bootdevice/by-name/cmnlib64");
ui_print("installing sbl1");
package_extract_s_file("firmware-update/sbl1.mbn", "/dev/block/bootdevice/by-name/sbl1");
ui_print("installing cmnlib");
package_extract_s_file("firmware-update/cmnlib.mbn", "/dev/block/bootdevice/by-name/cmnlib");
ui_print("installing rpm");
package_extract_s_file("firmware-update/rpm.mbn", "/dev/block/bootdevice/by-name/rpm");
ui_print("installing tz");
package_extract_s_file("firmware-update/tz.mbn", "/dev/block/bootdevice/by-name/tz");
ui_print("installing devcfg");
package_extract_s_file("firmware-update/devcfg.mbn", "/dev/block/bootdevice/by-name/devcfg");
ui_print("installing aboot");
package_extract_s_file("firmware-update/emmc_appsboot.mbn", "/dev/block/bootdevice/by-name/aboot");
ui_print("installing lksecapp");
package_extract_s_file("firmware-update/lksecapp.mbn", "/dev/block/bootdevice/by-name/lksecapp");
ui_print("installing keymaster");
package_extract_s_file("firmware-update/keymaster.mbn", "/dev/block/bootdevice/by-name/keymaster");
), "");
ifelse(msm.boot_update("backup"), (
ui_print("installing cmnlib64bak");
package_extract_s_file("firmware-update/cmnlib64.mbn", "/dev/block/bootdevice/by-name/cmnlib64bak");
ui_print("installing sbl1bak");
package_extract_s_file("firmware-update/sbl1.mbn", "/dev/block/bootdevice/by-name/sbl1bak");
ui_print("installing cmnlibbak");
package_extract_s_file("firmware-update/cmnlib.mbn", "/dev/block/bootdevice/by-name/cmnlibbak");
ui_print("installing rpmbak");
package_extract_s_file("firmware-update/rpm.mbn", "/dev/block/bootdevice/by-name/rpmbak");
ui_print("installing tzbak");
package_extract_s_file("firmware-update/tz.mbn", "/dev/block/bootdevice/by-name/tzbak");
ui_print("installing devcfgbak");
package_extract_s_file("firmware-update/devcfg.mbn", "/dev/block/bootdevice/by-name/devcfgbak");
ui_print("installing abootbak");
package_extract_s_file("firmware-update/emmc_appsboot.mbn", "/dev/block/bootdevice/by-name/abootbak");
ui_print("installing lksecappbak");
package_extract_s_file("firmware-update/lksecapp.mbn", "/dev/block/bootdevice/by-name/lksecappbak");
ui_print("installing keymasterbak");
package_extract_s_file("firmware-update/keymaster.mbn", "/dev/block/bootdevice/by-name/keymasterbak");
),"no backup partition");
msm.boot_update("finalize");
ui_print("installing modem");
package_extract_s_file("firmware-update/NON-HLOS.bin", "/dev/block/bootdevice/by-name/modem");
ui_print("installing dsp");
package_extract_s_file("firmware-update/adspso.bin", "/dev/block/bootdevice/by-name/dsp");
ui_print("installing asusfw");
package_extract_file("firmware-update/asusfw.img", "/dev/block/bootdevice/by-name/asusfw");
set_progress(1.000000);