[syslinux] Boot Error GPT partition

[KESHAV P.R.]

Hi all,
         I was using grub2 for booting Archlinux x86_64 in my GPT
Internal HDD (/dev/sda) then I switched to syslinux/extlinux. It was
working fine but suddenly it staring showing "Boot Error" message on
screen. I googled for a solution and tried all syslinux versions from
4.04-pre4 down to 4.03-stable but non of them worked. I don't know
what suddenly changed  caused this error. This is the gdisk output of
/dev/sda

[keshav_pr at keshav-laptop ~]$ sgdisk -p /dev/sda
Disk /dev/sda: 625142448 sectors, 298.1 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 625142414
Partitions will be aligned on 1-sector boundaries
Total free space is 18 sectors (9.0 KiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1              40          401623   196.1 MiB   EF00
EFI_SYSTEM_PART                   -> fat32 - /boot/efi - efi system
partition
   2          401624          483543   40.0 MiB    EF02
BIOS_BOOT_GRUB2                -> bios_grub for grub2
   3          483544         2488472   979.0 MiB   FFFF  Tianocore_EDK_DUET_UEFI
   4        17260760        17832149   279.0 MiB   FFFF  EDK_UEFI64
   5        17832150       112197959   45.0 GiB    0700
MS_WINDOWS_7_x64_RTM    -> Windows 7 x64 Pro - ntfs - boot using  uefi
so syslinux is not involved in any chainloading
   6       112197960       206563769   45.0 GiB    0700  DATA_3
   7       206563770       258179514   24.6 GiB    FFFF  LINUX_x64
                        -> ext4 - Archlinux x86_64 /
   8       258179515       258998714   400.0 MiB   FFFF
Linux_Boot_GRUB2_BIOS      -> Marked GPT attribute Legacy BIOS
Bootable - ext4 - Archlinux x86_64 /boot
   9       258998720       290455199   15.0 GiB    FFFF  Unknown
  10       290455200       457370549   79.6 GiB    0700  DATA_1
  11       457370550       625137344   80.0 GiB    0700  DATA_2
  12       625137352       625142414   2.5 MiB     FFFF  Unknown
  13         2488473        17260759   7.0 GiB     8200  Linux swap


I tried installing using all these combinations but none of them work

sudo extlinux --{install/upgrade} /boot/{syslinux/extlinux}

I switched back to grub2 for now but I want to know what is the exact
problem that has cropped up suddenly and how to solve it. Just FYI,
grub2 does not use the boot sector in /boot partition, it stores fs
modules in core.img in the bios_grub partition.

I tried "chainloader (hd0,8)+1" in grub2 terminal but the same "Boot
Error" message came. So this might rule out gptmbr.bin problem. Thanks
in advance for any help.

Regards.

Keshav