Grub install failed in dual boot

[Manman]

I've been trying to dual boot ubuntu along windows 10 but so far, install always encounters a fatal error when it comes to the installation of grub2. Now, I can't even boot Windows 10.

Installation of Ubuntu 20.04.02

Output of lscpi -v

H/W path Device Class Description
===================================================
                            system To be filled by O.E.M. (To be filled by O.E.M.)
/0 bus CRESCENTBAY
/0/0 memory 64KiB BIOS
/0/3d memory 32KiB L1 cache
/0/3e memory 32KiB L1 cache
/0/3f memory 256KiB L2 cache
/0/40 memory 4MiB L3 cache
/0/41 processor Intel(R) Core(TM) i7-4560U CPU @ 1.60GHz
/0/43 memory 8GiB System Memory
/0/43/0 memory 8GiB SODIMM DDR3 Synchronous 1600 MHz (0.6 ns)
/0/43/1 memory DIMM [empty]
/0/100 bridge Haswell-ULT DRAM Controller
/0/100/2 display Haswell-ULT Integrated Graphics Controller
/0/100/3 multimedia Haswell-ULT HD Audio Controller
/0/100/14 bus 8 Series USB xHCI HC
/0/100/14/0 usb2 bus xHCI Host Controller
/0/100/14/0/1 storage Cruzer Blade
/0/100/14/0/7 bus USB2.0 Hub
/0/100/14/0/7/1 input HP Basic USB Keyboard
/0/100/14/0/7/2 input USB Receiver
/0/100/14/0/8 storage USB Storage
/0/100/14/1 usb3 bus xHCI Host Controller
/0/100/1b multimedia 8 Series HD Audio Controller
/0/100/1c bridge 8 Series PCI Express Root Port 1
/0/100/1c.2 bridge 8 Series PCI Express Root Port 3
/0/100/1c.2/0 enp2s0 network RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
/0/100/1c.3 bridge 8 Series PCI Express Root Port 4
/0/100/1c.3/0 enp3s0 network RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
/0/100/1c.5 bridge 8 Series PCI Express Root Port 6
/0/100/1c.5/0 wlp4s0 network AR93xx Wireless Network Adapter
/0/100/1d bus 8 Series USB EHCI #1
/0/100/1d/1 usb1 bus EHCI Host Controller
/0/100/1d/1/1 bus USB hub
/0/100/1f bridge 8 Series LPC Controller
/0/100/1f.2 storage 8 Series SATA Controller 1 [AHCI mode]
/0/100/1f.3 bus 8 Series SMBus Controller
/0/1 system PnP device PNP0c02
/0/2 system PnP device PNP0c02
/0/3 system PnP device PNP0b00
/0/4 generic PnP device INT3f0d
/0/5 system PnP device PNP0c02
/0/6 system PnP device PNP0c02
/0/7 scsi2 storage
/0/7/0.0.0 /dev/sda disk 1TB WDC WD10JPVX-22J
/0/7/0.0.0/1 /dev/sda1 volume 579MiB Windows NTFS volume
/0/7/0.0.0/2 /dev/sda2 volume 686GiB Windows NTFS volume
/0/7/0.0.0/4 /dev/sda4 volume 244GiB Extended partition
/0/7/0.0.0/4/5 /dev/sda5 volume 7812MiB Linux swap volume
/0/7/0.0.0/4/6 /dev/sda6 volume 177GiB EXT4 volume
/0/7/0.0.0/4/7 /dev/sda7 volume 1429MiB Windows FAT volume
/0/7/0.0.0/4/8 /dev/sda8 volume 57GiB EXT4 volume
/0/8 scsi3 storage
/0/8/0.0.0 /dev/sdb disk 15GB Cruzer Blade
/0/8/0.0.0/0 /dev/sdb disk 15GB
/0/8/0.0.0/0/2 /dev/sdb2 volume 15EiB Windows FAT volume
/0/8/0.0.0/0/3 /dev/sdb3 volume 11GiB EXT4 volume
/0/9 scsi4 storage
/0/9/0.0.0 /dev/sdc disk STORAGE DEVICE
/0/9/0.0.0/0 /dev/sdc disk

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubiquity 20.04.15.10
ProcVersionSignature: Ubuntu 5.8.0-43.49~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-43-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
CasperMD5CheckResult: skip
CasperVersion: 1.445.1
Date: Fri May 21 11:17:59 2021
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 20.04.2.0 LTS "Focal Fossa" - Release amd64 (20210209.1)
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)