Hi,

just in case someone needs a finer speed setting:

Frequency    | Hashrate  | value | timeout
125.00 MHz | 1000 MHs | 0481 | 042 ms
137.50 MHz | 1100 MHs | 0501 | 039 ms
150.00 MHz | 1200 MHs | 0581 | 035 ms
162.50 MHz | 1300 MHs | 0601 | 033 ms
175.00 MHz | 1400 MHs | 0681 | 030 ms
187.50 MHz | 1500 MHs | 0701 | 028 ms
200.00 MHz | 1600 MHs | 0781 | 026 ms
212.50 MHz | 1700 MHs | 0801 | 025 ms
225.00 MHz | 1800 MHs | 0881 | 023 ms
237.50 MHz | 1900 MHs | 0901 | 022 ms
250.00 MHz | 2000 MHs | 0981 | 021 ms
262.50 MHz | 2100 MHs | 0A01 | 020 ms
275.00 MHz | 2200 MHs | 0A81 | 019 ms

or even finer for tweaking your individual miner:
237.50 MHz | 1900 MHs | 1285 | 022 ms
243.75 MHz | 1950 MHs | 1305 | 022 ms
250.00 MHz | 2000 MHs | 1385 | 021 ms
256.25 MHz | 2050 MHs | 1405 | 020 ms
262.50 MHz | 2100 MHs | 1485 | 020 ms
268.75 MHz | 2150 MHs | 1505 | 019 ms
275.00 MHz | 2200 MHs | 1585 | 019 ms
281.25 MHz | 2250 MHs | 1605 | 019 ms
287.50 MHz | 2300 MHs | 1685 | 018 ms
293.75 MHz | 2350 MHs | 1705 | 018 ms
300.00 MHz | 2400 MHs | 1785 | 017 ms

But beware. While playing around with this values or better some values not respecting the forumular given in the U1 manual I somehow wrecked my antminers clock generation.

Greetings,

                miniasic.