I have Pipo x7s box with Intel Bay Trail processor and eMMC storage. It is a 64 bit processor but UEFI partition is 32-bit. I know it is possible to install 32 bit grub in 64 bit Ubuntu image but I was wondering if I can wipe all the partitions and clean install Ubuntu 64 bit and create a proper 64 bit EFI partition ? Or 32 bit is a limit of my UEFI (BIOS) ? I am asking that first because I don't really want to brick the device.
I believe you're conflating two things:
- The firmware (EFI/UEFI) -- This is software that's built into a chip on the computer's motherboard. Most computers sold these days have 64-bit EFIs; however, some low-end systems (mostly tablets and netbooks) have 32-bit EFIs, even if they've got 64-bit CPUs.
- The EFI System Partition (ESP) -- This is a partition on the hard disk that holds boot loaders and related files. The EFI uses the ESP, but the ESP isn't really 32-bit or 64-bit, except insofar as it normally uses the FAT32 filesystem. FAT32 is used by both 32-bit and 64-bit EFIs, though; the "32" in "FAT32" has nothing to do with the bit depth of the firmware.
Installing Ubuntu on a system with a 32-bit EFI is possible, but awkward. See this question and its answers for details. Personally, my preference is to add a 32-bit EFI boot loader to a 32-bit Ubuntu installer and install a 32-bit Ubuntu; but many people prefer to install a 64-bit Ubuntu by using a 32-bit boot loader on a 64-bit Ubuntu installer. The advantages and disadvantages are rather technical, and which is best depends on your own needs and the hardware's features -- especially how much RAM and storage (disk or equivalent) space it provides. The more powerful the computer, the greater the advantage of installing a 64-bit Ubuntu; the weaker it is, the more sense it makes to stick with a 32-bit version.
On some computers, another option is to install in BIOS/CSM/legacy mode; however, all of the PCs with 32-bit UEFIs I know of don't have Compatibility Support Modules (CSMs; the software that enables an EFI to boot BIOS-mode boot loaders), so this isn't an option with them. It is an option with older Intel-based Macs with 32-bit EFIs. Mixing EFI-mode and BIOS-mode OS installations can also be tricky, so this isn't an appealing option if you're dual-booting.
Another question is whether you'll run into driver issues. I've got an ASUS T100 tablet/convertible that works poorly with every Linux I've tried on it because of driver issues unrelated to booting. (That said, I haven't tried anything more recent than Ubuntu 16.04, IIRC.) You may want to do a Web search on your model to learn whether it will work adequately before you invest any time in trying to get it to boot.
Overall, it's hard for me to disagree with MichaelBay's recommendation that you forget about installing Ubuntu on this computer. That said, I'm not familiar with your specific hardware, so I don't know what other issues you might run into, and those are likely to be more important than the boot loader issues, in the long run.
You can get it done but it takes a bit of work.
First you need to make a live USB of your wanted Ubuntu 64bit version (Xubuntu would be best) but it must have persistence.
The easiest way to make this is to use the startup disk creator on an Ubuntu 14.04 Live USB.
Once you have your USB with persistence you need to add this file to the /EFI/BOOT directory of the flash drive.
- Plug your USB drive into the device
- Start up the device
- Go into the BIOS of the device and disable secure boot, save and exit
- Boot off the USB drive
It should boot into the expected Live USB environment.
Once done, plug in a internet connection (I use my android phone with USB tethering).
Then install the distro onto the device making sure to select the options to install third party software and download updates.
As you have an internet connection while installing it will automatically install 32bit EFI grub for you.
After it is all installed you should be able to boot directly onto the device but you may need to do additional work to get wifi, bluetooth, and sound working.