[Honor 7 Android Development] t-ryder:
I know that error.

updater-script of DigiROM looks like this:

ui_print("Installing kernel...");
package_extract_file("boot.img", "/dev/block/platform/hi_mci.0/by-name/boot");
ui_print("Formatting System partition...");
format("ext4", "EMMC", "/dev/block/platform/hi_mci.0/by-name/system", 0, "/system");
ui_print("Mounting System partition...");
mount("ext4","EMMC","/dev/block/platform/hi_mci.0/by-name/system", "/system");
ui_print("Installing system Apps...");
package_extract_file("system.apps.tar.gz", "/tmp/system.apps.tar.gz");
run_program("/sbin/busybox", "tar", "zxvf", "/tmp/system.apps.tar.gz", "-C", "/");
delete("/tmp/system.apps.tar.gz");
ui_print("Installing System files...");
package_extract_file("system.therest.tar.gz", "/tmp/system.therest.tar.gz");
run_program("/sbin/busybox", "tar", "zxvf", "/tmp/system.therest.tar.gz", "-C", "/");
delete("/tmp/system.therest.tar.gz");
ui_print("Formatting Cust partition...");
format("ext4", "EMMC", "/dev/block/platform/hi_mci.0/by-name/cust", 0, "/cust");
ui_print("Mounting Cust partition...");
mount("ext4","EMMC","/dev/block/platform/hi_mci.0/by-name/cust", "/cust");
ui_print("Extracting Custom files...");
package_extract_file("cust.tar.gz", "/tmp/cust.tar.gz");
run_program("/sbin/busybox", "tar", "zxvf", "/tmp/cust.tar.gz", "-C", "/");
delete("/tmp/cust.tar.gz");
sync();
unmount("/cust");
unmount("/system");

But it should be like this to prevent that error:

ifelse(is_mounted("/system"), unmount("/system"));
ifelse(is_mounted("/cust"), unmount("/cust"));
ui_print("Installing kernel...");
package_extract_file("boot.img", "/dev/block/platform/hi_mci.0/by-name/boot");
ui_print("Formatting System partition...");
format("ext4", "EMMC", "/dev/block/platform/hi_mci.0/by-name/system", 0, "/system");
ui_print("Mounting System partition...");
mount("ext4","EMMC","/dev/block/platform/hi_mci.0/by-name/system", "/system");
ui_print("Installing system Apps...");
package_extract_file("system.apps.tar.gz", "/tmp/system.apps.tar.gz");
run_program("/sbin/busybox", "tar", "zxvf", "/tmp/system.apps.tar.gz", "-C", "/");
delete("/tmp/system.apps.tar.gz");
ui_print("Installing System files...");
package_extract_file("system.therest.tar.gz", "/tmp/system.therest.tar.gz");
run_program("/sbin/busybox", "tar", "zxvf", "/tmp/system.therest.tar.gz", "-C", "/");
delete("/tmp/system.therest.tar.gz");
ui_print("Formatting Cust partition...");
format("ext4", "EMMC", "/dev/block/platform/hi_mci.0/by-name/cust", 0, "/cust");
ui_print("Mounting Cust partition...");
mount("ext4","EMMC","/dev/block/platform/hi_mci.0/by-name/cust", "/cust");
ui_print("Extracting Custom files...");
package_extract_file("cust.tar.gz", "/tmp/cust.tar.gz");
run_program("/sbin/busybox", "tar", "zxvf", "/tmp/cust.tar.gz", "-C", "/");
delete("/tmp/cust.tar.gz");
sync();
unmount("/cust");
unmount("/system");

So the first thing that the script does is unmount (first two lines with ifelse), then later it mounts the partitions to flash, then at the end it unmounts so you are ready for reboot after flashing.

You can download my ROM LINK and have a look at the updater-script inside there to see what my version does all in all.

By the way: First boot after flashing takes long with Honor 7 ROMs based on modaco custom ROM and it maybe seems like the device is stuck since there is nothing going on at the screen. It can take up to 10 minutes for the first boot - the system is optimizing caches and it takes a bit time.

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