Android x86 > error: SysRq: Emergency remount R/0

I have a PC with Windows 10 and Ubuntu 18.04, but would like to add more Android x86(lineageOS 14.1). The ISO file works perfectly in Live USB. After installing with USB (by selecting "Run LineageOS"), the android launches without problems. But after the restart (added lineageOS 14.1 via /etc/grub.d/40_custom), it does start with the following message:

Detecting Android-x86... found at /dev/sda7

[
  3.697517] sysrq: SysRq: Emergency remount R/0

Then it reboots to the GRUB2 menu.

How do I fix this, and boot lineageOS 14.1?

My PC with an CPU Intel Celeron 2.6 GHz 1 core, 1GB ram, and I am trying to start lineageOS 14.1 on a 8GB partition (without SDcard).

My boot code is:

 recordfail=1


 if [ -n ${
have_grubenv
}
 ]; then save_env recordfail; fi

set quiet=1

insmod ext2

set root=(hd0,7)

search --no-floppy --fs-uuid --set 033e8fc7-4cfe-9454-bc59-df7329ca862d

linux /cm-x86-14.1-r2/kernel root=UUID=033e8fc7-4cfe-9454-bc59-df7329ca862d ro quiet splash

initrd /cm-x86-14.1-r2/initrd.img