How to use an existing USB Hard drive which you do not want to erase

Introduction

You may have a large USB HDD which has many files on it which you do not wish to delete.

However, due to BIOS incompatibilities in many systems, the maximum size of the first partition that you should have for a bootable USB drive is 128GiB. The Easy2Boot files must be on the first partition because some buggy BIOSes cannot access USB drive sectors which are beyond 128GiB (137GB).

If you have just one large HDD with a single partition of over 128GB, you should split it into two partitions

Partition 1: 128GiB or smaller Primary NTFS (for E2B) maximum 128GiB
Partition 2: (remaining space less 10MB) Primary NTFS\FAT32\exFAT (your files)
Partition 3: (empty)
Partition 4: (empty)

A partition 2 must be present for maximum BIOS compatibility.

If you have a single large partition then move the start of the partition to leave 128Gb free and then create a new first partition of 128GiB for E2B.

Tip: Use RMPrepUSB - Drive Info - 0 to check that you are only using one or two of the four available partition entries in the partition table.

Note that these kinds of partition moving and re-sizing operations carry a risk of losing data and it does not always work without data loss!

E2B also requires unused free space on the first partition so that files can be easily and quickly defragmented, so make sure the E2B partition is large enough.

Note: The process of shrinking partitions and moving files can be very slow on USB drives and also unsafe. I highly recommend that you transfer your files from the USB drive to a different drive and then use the E2B_Maker.exe GUI tool to re-partition and re-format your USB drive. This will make a 128GiB partition + a small 31K partition. You can then delete the small 2nd partition and make a large 2nd Primary NTFS partition on the USB drive and copy your own files to the 2nd partition.

Method

Once you have a partitioned NTFS USB HDD, you can install E2B onto the first partition.

1. You need to install grub4dos to make the USB drive bootable.

Note: If the drive was previously used as a bootable drive, then installing grub4dos will, of course, now make it boot to grub4dos.

Run RMPrepUSB (press Ctrl+Z if you have a large USB HDD) and make sure your USB HDD is selected. Now proceed with these 2 actions:

Install grub4dos - MBR=Yes (do NOT copy the grldr file)
Install grub4dos - MBR=No (do NOT copy the grldr file)

2. Run the E2B self-extracting download .exe file and use the Extract button to extract the contents to the Desktop and then copy the contents of the entire Easy2Boot folder to the USB drive. The USB drive should now contain a \_ISO folder in the root, plus some other files.

3. Then run .\UPDATE_E2B_DRIVE.CMD from the download folder (not the USB drive). Select the first partition of the USB drive by entering it's drive letter. It will then check\copy\update the E2B files to the selected partition.

4. Run \_ISO\docs\Make_E2B_USB_Drive\Add_Bootmgr_to_E2B_drives.cmd to automatically add the correct version of bootmgr to your E2B drive. This is required if you wish to boot .VHD and .WIM files.

5. Check that the USB HDD will now boot to E2B by using RMPrepUSB - F11 or double-click on the USB drive \QEMU_MENU_TEST (run as admin).cmd file or use the green QEMU button in Make_E2B.exe.

You should see the E2B Main menu load - now press F10 to quit E2B.

Notes

You must use the first partition of the USB drive for E2B files and payloads (ISOs)
The first partition should be < 128GB (some BIOSes cannot access files beyond 128GB on USB drives)
The USB HDD should contain 2 partitions. If it only contains one partition, create a 2nd Primary partition (of any size - even if very small) for BIOS compatibility.
Your USB HDD should not contain more than 2 Primary partitions.
When in use, E2B may use Primary partition #3 and partition #4.
E2B will not boot to the Main Menu unless partition #4 is unused. WARNING: E2B will prompt you to delete partition #4, if it exists.
Unless you have a specific requirement, use NTFS for the E2B partition. You can UEFI-boot from an NTFS E2B partition using .imgPTN image files.
You can place your personal files on the E2B partition as well, if you wish - it will just use up space. Do not place your own (non-E2B related) files under the \_ISO folder or else they will be defragmented by the E2B utility. Use your own folder, e.g. \Steve.
The large 500MB file \_ISO\CONTIG.ISO can be deleted if you are short of space and don't use linux. CONTIG.ISO is only used if the payload files are not contiguous.

Note: If the drive was previously used as a bootable drive, then installing grub4dos will, of course, now make it boot to E2B instead.

Run RMPrepUSB (press Ctrl+Z if you have a large USB HDD) and make sure your USB HDD is selected. Now proceed with these 2 actions:

Install grub4dos - MBR=Yes (do NOT copy the grldr file)
Install grub4dos - MBR=No (do NOT copy the grldr file)