There is some misinformation about the bootloader going around in the various forums.
One is that it would NOT be possible to go back from a higher bootloader to a lower version, that is not true.
With an intermediate step via bootloader 0.0001 if I remember correctly, I have to look that up on my FTP server, you can go back to the beginning and start again.
I have used bootload 5.5128 for years, which makes it possible to use SDHC up to 32GB, but I believe that this is also possible from 5.5028.
It is advisable to do the trick with a full battery or connected to an external power supply, it is done in a few seconds.
I'll put some together and come back to it later.
P.S.
Install WinSCP and go straight to de files you need via the link below a Readme.txt is available.
ftp://SerVice_Once_Only_Friends:SerVice ... net:47474/