I have read that booting other operating systems via USB is theoretically possible on the Asus Transformer book, but I have not been able to get it to work. The main issue from booting on Windows 8.1 tablets is the secure boot mode that has to be turned off via restarting in UEFI mode, which I have done and double checked and triple checked. The USB is displayed as a UEFI bootable device, which is the only thing the T100TA can boot from, and when it is selected both from the boot menu and the BIOS setup the tablet screen simply 'refreshes' (flashes black for a fraction of a second and tears slightly) and shows no change in status. There is no option to disable fast boot in the boot menu, although I have done so through Windows 8.1's battery settings, I have not determined a way to switch to any CSM boot mode, and there is no setting for USB Legacy Mode. In the boot order list USB media has been set as first. I have made sure the operating systems I have tried to install are GPT formatted, but this has the same outcome, just the same as regular MBR and plain copying of ISO files directly to the USB. I have read multiple success stories with installation of alternate OS's on the T100TA, and followed instructions for doing so to the letter, but the process always grinds to a halt at the same place. Are there any suggestions for alternate ways of booting operating systems, or is there something else that I possibly haven't turned off/have done wrong?
Windows – Booting from USB on Asus T100TA
biosbootoperating systemstabletwindows 8.1
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I tried the following and it solved the issue!!
Please refer the answer here - https://forums.lenovo.com/t5/Lenovo-Edge-Yoga-Flex-Laptops/Guide-Windows-8-1-PRO-RTM-clean-install-on-Yoga-13-from-a-USB/m-p/1233563/highlight/false#M9262
In order to boot from UEFI the flash drive must be formatted as FAT32. Windows USB and DVD tool supports only NTFS, So after creating the bootable image, copy all the files from the flash drive to the HDD then format the flash drive as FAT32 then copy the files back from the HDD to the flash drive. The flash drive will still be bootable.
Asus T100 is Intel Bay Trail device and most of those, despite having a 64bit CPU, have IA32 (32bit) EFI firmware. Also feature called Secure Boot is enabled in EFI setup by default and that might block some operating systems from showing up in boot menu. In order to make firmware recognize flash-drive as bootable it needs to be formatted as FAT32 and have signed 32bit operating system loader in EFI/bootia32.efi.
You do not mention which 2nd operating system you are trying to boot so I can only assume it's a Linux distribution. It probably does not show up in menu because:
SecureBoot is enabled and EFI/bootia32.efi is not signed by valid key - easiest is to disable SecureBoot in EFI setup (there should be a toggle). Beware that some Windows 10 features (e.g. BitLocker) don't work in that state.
32bit EFI loader is not present on flash-drive at all (this applies for most 64bit Linux distribution Live USBs - e.g. Ubuntu). In that case you will need to compile GRUB for 32bit EFI and place it to proper directory (and also disable SecureBoot, obviously). For Ubuntu, there are ISOs already prepared. You can find them here: http://linuxiumcomau.blogspot.com/2016/10/running-ubuntu-on-intel-bay-trail-and.html (NOTE: those are not official Ubuntu images, have patched kernel to support specific hardware and are not officially supported in any way - please read the information on that page before trying them out.)
This page might give you some hints on getting Linux running on your device (if Linux is case): http://www.jfwhome.com/2014/03/07/perfect-ubuntu-or-other-linux-on-the-asus-transformer-book-t100/
Best Answer
Check out this question too for ideas. Asus UEFI/BIOS options - How to boot from DVD?
But it could be, the thing you aren't mentioning, is the 32 or 64 bit of your setup. e.g. The BIOS/UEFI is sometimes 32 or 64 bit only, so trying to boot the wrong version of the ISO will cause it to be ignored or fail. So it matters what architecture is, not just the CPU itself, but the BIOS/UEFI, and then the media that is trying to be booted too.
At this low level of booting things, there, many things are hardcoded to be for specific architectures etc, that's why it's so sensitive to the right setup being in place.