$ git submodule update
Submodule path 'dtc': checked out 'bc895d6d09695d05ceb8b52486ffe861d6cfbdde'
Submodule path 'pixman': checked out '97336fad32acf802003855cd8bd6477fa49a12e3'
Submodule path 'roms/SLOF': checked out
'8cfdfc43f4c4c8c8dfa4b7cf16f7c19c84eee812'
Submodule path 'roms/ipxe': checked out
'09c5109b8585178172c7608de8d52e9d9af0b680'
Submodule path 'roms/openbios': checked out
'0f3d51ef22ec9166beb3ed434d253029ed7cfe84'
Submodule path 'roms/qemu-palcode': checked out
'c87a92639b28ac42bc8f6c67443543b405dc479b'
Cloning into 'roms/seabios'...
remote: Counting objects: 9706, done.
remote: Compressing objects: 100% (2392/2392), done.
remote: Total 9706 (delta 7753), reused 9244 (delta 7308)
Receiving objects: 100% (9706/9706), 2.26 MiB | 220.00 KiB/s, done.
Resolving deltas: 100% (7753/7753), done.
fatal: reference is not a tree: ece025f5980bae88fa677bc9c0d24d2e580e205d
Cloning into 'roms/sgabios'...
remote: Counting objects: 24, done.
remote: Compressing objects: 100% (23/23), done.
remote: Total 24 (delta 8), reused 0 (delta 0)
Receiving objects: 100% (24/24), 44.33 KiB | 0 bytes/s, done.
Resolving deltas: 100% (8/8), done.
Submodule path 'roms/sgabios': checked out
'23d474943dcd55d0550a3d20b3d30e9040a4f15b'
Cloning into 'roms/vgabios'...
remote: Counting objects: 1281, done.
remote: Compressing objects: 100% (381/381), done.
remote: Total 1281 (delta 898), reused 1281 (delta 898)
Receiving objects: 100% (1281/1281), 762.30 KiB | 172.00 KiB/s, done.
Resolving deltas: 100% (898/898), done.
Submodule path 'roms/vgabios': checked out
'19ea12c230ded95928ecaef0db47a82231c2e485'
Unable to checkout 'ece025f5980bae88fa677bc9c0d24d2e580e205d' in submodule path
'roms/seabios'