To investigate and fix ASM disk header corruption

How To Restore/Repair/Fix An Overwritten (KFBTYP_INVALID) ASM Disk Header (First 4K) 10.2.0.5, 11.1.0.7, 11.2 And Onwards (Doc ID 1088867.1) 

To confirm if just block 0 is corrupted or there are more blocks, please execute this script and upload .out files
kfed.sh
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#! /bin/sh
rm /tmp/kfed_DH.out /tmp/kfed_FS.out /tmp/kfed_BK.out /tmp/kfed_FD.out /tmp/kfed_DD.out
for i in `ls /dev/emc*`
do
echo $i >> /tmp/kfed_DH.out
kfed read $i >> /tmp/kfed_DH.out
echo $i >> /tmp/kfed_FS.out
kfed read $i blkn=1 >> /tmp/kfed_FS.out
echo $i >> /tmp/kfed_BK.out
kfed read $i aun=1 blkn=254 >> /tmp/kfed_BK.out
echo $i >> /tmp/kfed_FD.out
kfed read $i aun=2 blkn=1 >> /tmp/kfed_FD.out
echo $i >> /tmp/kfed_DD.out
kfed read $i aun=2 blkn=2 >> /tmp/kfed_DD.out
done
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That way we can see which au's are affected

Please, upload asmdu output too:
amdu -diskstring '' -dump

and the OS logs

Additionally, please upload:
1) full ASM alertlog

2) Please connect to ASM instance, generate and upload /tmp/ASM_#.html file as result of output from v$asm_disk and v$asm_diskgroup:

---------------------- cut -------------------------
         spool /tmp/ASM_<#>.html
         set markup HTML on
         set pagesize 1000
         set lines 500
         alter session set nls_date_format='DD-MON-YYYY HH24:MI:SS';
         select sysdate "Date and Time" from dual;
         select 'HOSTNAME ASSOCIATED WITH THIS ASM INSTANCE: ==)> ' , MACHINE " " from v$session where program like '%SMON%';

         select * from v$asm_diskgroup order by 1;
         select * from v$asm_disk order by 1, 2, 3;
         select * from gv$asm_operation order by 1;
         select * from v$version where banner like '%Database%' order by 1;
         select * from gv$asm_client order by 1;
         select group_number, name, value FROM v$asm_attribute where NAME like 'disk_repair_time';

         show parameter asm
         show parameter size
         show parameter proc
         show parameter cluster
         show parameter instance_type
         show parameter instance_name

         show parameter pfile

         show sga

         spool off

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