• rear version (/usr/sbin/rear -V): Most likely any (tested with 1.17.2)
• OS version (cat /etc/rear/os.conf or lsb_release -a): (very likely any), tested with SLES11 SP3
• rear configuration files (cat /etc/rear/site.conf or cat /etc/rear/local.conf):

BACKUP=TSM
COPY_AS_IS_TSM=( /etc/adsm/TSM.PWD /opt/tivoli/tsm/client /usr/local/ibm/gsk8* )
COPY_AS_IS_EXCLUDE_TSM=( )
PROGS_TSM=( dsmc tput )
TSM_RESULT_FILE_PATH=/opt/tivoli/tsm/rear
TSM_DSMC_RESTORE_OPTIONS=( )
TSM_RESTORE_PIT_DATE=
TSM_RESTORE_PIT_TIME=
TSM_RESULT_SAVE=y

the rest is the usual stuff

• Brief description of the issue
  rear mkrescue (or mkbackup) fails with the message like
  2016-03-29 17:14:15.078510507 ERROR: Could not copy initrd to UEFI
• Work-around, if any
  I have modified rear code: extended UEFI image size by experimentally determined value for this particular setup. I have not tested an actual recovery though (but do not see reason why it would not work).

I will post the patch I used immediately, for your consideration.