diff --git a/board/miyoo/boot/firstboot b/board/miyoo/boot/firstboot
index 1bfab7a33..6ab96ba79 100755
--- a/board/miyoo/boot/firstboot
+++ b/board/miyoo/boot/firstboot
@@ -506,13 +506,13 @@ if (dialog --clear --stdout --ok-label YES --cancel-label NO --title "   AUTO-RE
 			SD_MAX_AVAIL_SIZE_IN_KiB=123731968
 		fi
 	fi
-	SD_MAX_AVAIL_SIZE_IN_GiB=$(echo "scale=1; ${SD_MAX_AVAIL_SIZE_IN_KiB} / 1024 / 1024" | bc)
-	P4_SIZE_IN_GiB=$(echo "scale=1; ${P4_SIZE} * 512 / 1024 / 1024 / 1024" | bc)
+	SD_MAX_AVAIL_SIZE_IN_GB=$(echo "scale=1; ${SD_MAX_AVAIL_SIZE_IN_KiB} * 1024 / 1000 / 1000 / 1000" | bc)
+	P4_SIZE_IN_GB=$(echo "scale=1; ${P4_SIZE} * 512 / 1000 / 1000 / 1000" | bc)
 	# roundup GiB value to 0,1GB for integer calculations:
-	SD_MAX_AVAIL_SIZE_IN_GiBx10=$(echo "$SD_MAX_AVAIL_SIZE_IN_GiB" | tr -d ".")
-	P4_SIZE_IN_GiBx10=$(echo "$P4_SIZE_IN_GiB" | tr -d ".")
+	SD_MAX_AVAIL_SIZE_IN_GBx10=$(echo "$SD_MAX_AVAIL_SIZE_IN_GB" | tr -d ".")
+	P4_SIZE_IN_GBx10=$(echo "$P4_SIZE_IN_GB" | tr -d ".")
 	#Sanity checks if we don't down- or over-resize partition:
-	if (test "$P4_SIZE_IN_GiBx10" -ge "$SD_MAX_AVAIL_SIZE_IN_GiBx10" || test "$SD_MAX_UNALL_SIZE_IN_MiB" -le 0); then
+	if (test "$P4_SIZE_IN_GBx10" -ge "$SD_MAX_AVAIL_SIZE_IN_GBx10" || test "$SD_MAX_UNALL_SIZE_IN_MiB" -le 0); then
 		echo "Your MAIN partition is greater than available space for resizing or you lack unallocated sectors space" | tee -a ${LOG}
 		sleep 1.5
 		RESIZE_ABORT=true