Convert a hex-encoded string to varbinary - MSSQL

convert.sql

declare @hexstring varchar(max)
declare @bin       varbinary(max)

set @hexstring = '0x10.....'
set @bin = (
  select cast('' as xml).value('xs:hexBinary(substring(sql:variable("@hexstring"), sql:column("t.pos")))', 'varbinary(max)')
  from (select case substring(@hexstring, 1, 2) when '0x' then 3 else 0 end) as t(pos)
)
select @bin

update db.dbo.table
set column = @bin
where id = 1

thanks a lot, built-in function of mssql has input length limit, such as convert and fn_cdc_hexstrtobin